Anesthetic and Antiemetic Infusion Pumps

Number: 0607

Table Of Contents

Policy

Scope of Policy

This Clinical Policy Bulletin addresses anesthetic and antiemetic infusion pumps.

1. Experimental, Investigational, or Unproven

   Aetna considers the following anesthetic and antiemetic infusion pumps experimental, investigational, or unproven because the effectiveness of these pumps has not been demonstrated in well-designed clinical studies published in the peer-reviewed medical literature:

   1. Infusion pumps for intralesional administration of narcotic analgesics and anesthetics; 
   2. Infusion pumps for local administration of narcotic analgesics and anesthetics with any of the following indications listed below:
      
      
      1. Arthroscopic shoulder surgery
      2. Bariatric surgery
      3. Cardiothoracic surgery
      4. Donor nephrectomy
      5. Free flap breast reconstruction
      6. Laparoscopic cholecystectomy
      7. Open inguinal hernia repair
      8. Total hip arthroplasty;
         
   3. Infusion pumps for intraarticular administration of narcotic analgesics and anesthetics;
   4. Continuous subcutaneous antiemetic pumps;
   5. Elastomeric pump for home intravenous administration of antibiotics;
   6. Hepatic arterial infusion pump chemotherapy for the treatment of unresectable intrahepatic cholangiocarcinoma .

2. Policy Limitations and Exclusions 

   Disposable intralesional anesthetic and analgesic infusion pumps inserted at surgery are considered surgical supplies that are integral to surgery and not separately reimbursed.

   This policy does not apply to continuous peripheral nerve blocks (e.g., brachial plexus blocks, femoral nerve blocks, inter-costal blocks). 

3. Related Policies

   • CPB 0010 - Continuous Passive Motion (CPM) Machines
   • CPB 0161 - Infusion Pumps

Background

Anesthetic Infusion Pump

Pain relief after surgery is often provided by patient-controlled systemic analgesia, which uses an intravenous infusion pump and a patient-activated switch to administer narcotic analgesics.

In order to avoid the complications associated with systemically administered narcotic analgesia, infusion pumps have been developed to administer narcotic analgesics and anesthetics directly into the lesion.  The On-Q Pain Management System, the Pain Buster Pain Management System, the Don Joy Pain Pump, and the Stryker Pain Pumps are brand names of devices designed to provide pain relief at the operative site for patients recovering at home from day surgery.  These devices have been used most frequently for patients who have undergone orthopedic or "sports medicine" surgery to repair knee and shoulder problems.  It should be noted that these devices have not received Food and Drug Administration (FDA) approval for intra-articular delivery of local analgesics and anesthetics.

Attached to the catheter is a small plastic pump that automatically directs a local anesthesia to the source of the pain.  The pumps have been used to dull the pain and eliminate the need for systemic narcotic and non-narcotic analgesics.  Narcotics have also been infused directly into inflamed tissue.  The device is secured to the body until the narcotic medication or anesthetic is depleted, and the patient can remove it him/herself.  The manufacturers of these devices claim that patients treated in this way are able to move around sooner following surgery and participate in rehabilitation with greater ease, and require fewer drugs to aid in recovery.

Studies in the medical literature, however, have not shown better patient outcomes (in terms of enhanced pain relief, reductions in disability, improvements in function or faster recovery) when these devices are used in place of or in addition to standard (systemic) administration of narcotics. 

Well-designed randomized controlled clinical studies evaluating both subjective endpoints of reduction in pain and objectively measured functional endpoints (reductions in disability and improvement in function) are especially important in evaluating pain interventions because of the susceptibility of pain to placebo effects.  The study by Alford et al (2003) found reductions in pain and narcotic use in subjects both subjects receiving intra-articular anesthetic and subjects receiving intra-articular saline compared to a comparison group receiving no catheter, suggesting an important placebo effect from intra-articular infusion pumps.  These findings were consistent with a study by Rosseland et al (2004), which found significant effects of intra-articular infusion of saline.

A study by Alford et al (2003) is significant in that it reported on functional outcomes (reductions in disability, improvements in function) in addition to subjective pain scores and narcotic consumption.  The investigators found no significant differences in functional outcomes (range of motion, straight leg raises) between the group receiving intra-articular anesthetic and the group receiving intra-articular saline.  Other randomized controlled clinical studies of intra-articular and intra-lesional anesthetic pumps are of weaker design than this study if they report only on pain scores and supplemental analgesic use, and not on functional outcomes.

Available studies do not consistently demonstrate clinically significant reductions in narcotic consumption in subjects receiving intra-articular or intra-lesional anesthetic.  In some studies, there was no significant reduction in narcotic usage in subjects assigned to intra-articular or intra-lesional anesthetic infusion compared to subjects assigned to intra-articular or intra-lesional saline infusions. 

In available studies, the reported reductions in pain scores in groups receiving intra-articular or intra-lesional anesthetics were generally modest and inconsistent, with some studies reporting significant reductions in some types of pain with intra-articular or intra-lesional anesthetic but not others. 

A number of studies have failed to find any significant effect of intra-articular or intra-lesional infusion of anesthetics (Boss et al, 2004; Drosos et al, 2002; Aasbo et al, 1996; Henderson et al, 1990; Joshi et al, 1993; Klasen et al, 1999; Schwarz et al, 1999; Rautoma et al, 2000; and DeWeese et al, 2001).

There are a paucity of studies that have directly compared the effectiveness and safety of intra-articular or intra-lesional infusions with established methods of post-operative analgesia.  Several such studies have been published, showing intra-articular or intra-lesional infusion to offer inferior post-operative pain relief (Dauri et al, 2003; Iskandar et al, 2003).

Available studies are small and not sufficiently powered to evaluate uncommon but clinically significant adverse effects of intralesional catheters.  The maintenance of a catheter in the wound may have an effect on infection and wound healing.  In addition, anesthetics used in continuous wound perfusion have vasoconstrictive properties that may adversely affect wound healing by decreasing blood flow to injured tissues.  Systemic absorption of large doses of anesthetic may be toxic.

In summary, available studies suggest that pain relief from intra-lesional and intra-articular anesthetics, if any, is modest and it remains unclear whether any analgesia produced by intra-articular and intra-lesional anesthetics is clinically useful. 

Gupta et al (2002) reported on a prospective, double-blind, randomized controlled clinical study of 40 subjects undergoing laparoscopic cholecystectomy.  This study was of stronger design than many other randomized controlled clinical studies of intra-lesional anesthetic pumps in that it includes as outcome measures both subjective assessments of pain and objective assessments of supplemental narcotic pain medication consumption, reductions in disability and improvements in function.  This study found a modest benefit to intralesional anesthetic pumps that was limited to only the first few hours after surgery.  Statistically significant differences in pain intensity (visual analog scale [VAS] scores) between patients receiving intra-lesional anesthesia versus intra-lesional saline infusion were limited to deep pain and pain during coughing during the early post-operative period (within 4 hours following surgery), with no differences in pain at the shoulder or incisional sites.  There were no significant differences in VAS scores between groups more than 4 hours after surgery.  However, these investigators noted that, in general, the pain intensity was mild, even in the placebo group.  There were no significant differences between groups in the amount of supplemental narcotic analgesic medication used, in the number of patients requiring no supplemental narcotic analgesic medication, or in the number of patients requiring higher doses of narcotic medication.  There were also no differences between groups in objective measures of post-operative recovery: time to transfer from phase 1 to phase 2 recovery, time to sit up in bed, time to stand and walk without support, time to drink and eat, time to void, and time to discharge home.  The most common post-operative complication was nausea, which was significantly more common in subjects receiving intra-lesional anesthesia.  No differences were seen between the groups during the first week.  The median times to start eating regularly, walking normally, defecating, driving the car, and return to normal activities of daily living were also similar between groups. 

A study by Schurr et al (2004) of intra-lesional anesthetic infusion in 80 patients undergoing inguinal herniorrhaphy is also a prospective double-blind, randomized, controlled clinical trial, that assessed both pain and objective functional outcomes (activity, return of bowel function).  These investigators reported a "mild reduction" in worst pain in patients receiving intra-lesional anesthesia (mean 6.7) than patients receiving saline (mean 5.0).  There was no reduction in the total amount of time spent in moderate pain between groups.  On day 1, least pain ratings were also lower, and patients ambulated more frequently than those who received placebo.  The investigators reported no differences between groups from post-operative day 2 to 5.  In addition, the investigators reported no differences between groups in hydrocodone consumption.  The investigators concluded that intra-lesional anesthetic infusion provided modest improvements in pain scores and functional outcomes when compared with placebo.  The investigators noted, however, that these effects were limited to the first post-operative day only.  The investigators considered that the same effect may be achieved by administering a pre-operative dose of an extended-release oral opioid or a non-steroidal anti-inflammatory drug (NSAID) without anti-platelet effects to control background pain in the immediate post-operative period and for the first 24 hours.  The investigators reported 5 % of the infusion pumps failed immediately, and 19.4 % of subjects who completed the study reported leakage of the infusion fluid from around the catheter infusion site.  The investigators noted a 4 % infection rate among study subjects, which is 10 times the historical rate of infections associated with this procedure for the investigators’ institution.  The investigators stated that this study was too small to evaluate infection risk, and that a larger prospective study comparing intra-lesional anesthetic infusion versus no infusion is needed to completely define this risk.  The investigators concluded that "[a]lthough continuous infusion of bupivacaine after inguinal herniorrhaphy provides multi-modal post-operative pain therapy, the pain-related outcomes are modestly improved at best and are limited to the first post-operative day.  The high incidence of leakage from the skin site and suggestion of increased infection risk alter the risk-to-benefit ratio of this technique".  The investigators concluded that the additional costs associated with intra-lesional anesthesia may limit its widespread use in clinical practice.

A study by Sanchez et al (2004) of 45 patients undergoing inguinal hernia repair is also of weaker design than previously described studies.  Although this is a randomized, blinded study, only patients’ perception of pain and analgesic use were assessed, and objective measures of post-operative recovery were not assessed.  Although the investigators reported significant differences in pain scores in patients assigned to intra-lesional anesthesia versus placebo on post-operative days 2 through 5, there were no significant differences between groups in the amount of narcotic analgesics that were used.

A study by LeBlanc et al (2005) of 52 patients undergoing open inguinal herniorrhaphy is also of weaker study design because outcomes were limited to pain scores and analgesic use, and post-operative recovery was not assessed.  Pain VAS scores were not significantly different between groups.  Narcotic use was significantly higher in placebo subjects, but narcotic use decreased significantly in both groups beyond the first post-operative day.  There was no difference in duration of hospital stay between groups.

Noting that "the effectiveness of continuous intra-bursal infusion of analgesics for prolonged pain is yet unproven," Park et al (2002) undertook a prospective, randomized, double-blind, controlled clinical study of intra-bursal infusion of anesthesia versus saline in 60 patients following sub-acromial arthroscopy procedures.  All subjects received a post-operative intra-bursal bolus of anesthetics.  One group also received a continuous infusion of anesthetic into the sub-acromial space, and the control group received a continuous infusion of saline into the sub-acromial space.  The anesthetic group reported significantly less rest pain, but there was no difference in pain caused by movement.  In the anesthetic group, lesser amounts of supplemental analgesics were used in the first 2 days post-operatively, and there was no significant difference in supplemental analgesics on the 3rd day post-operatively.  This study is of weaker design than the previously described study by Alford et al (2003) in that it only assessed post-operative pain and medication use, and did not assess objective functional measures. 

Dauri et al (2003) compared the effectiveness of epidural, continuous femoral block, and intra-articular analgesia in 60 patients undergoing anterior cruciate ligament reconstruction.  Patients were randomly assigned to receive continuous epidural ropivicaine, continuous ropivicaine femoral block, or continuous intra-articular ropivicaine.  The investigators reported that visual analog pain scores were significantly higher in the group receiving intra-articular anesthetic 24 hours following surgery, and that use of supplementary analgesics was significantly higher in the group receiving intra-articular anesthetic throughout the post-operative observation.  The investigators also reported that intra-articular analgesia was associated with a lower degree of patient satisfaction.  The investigators concluded that epidural or continuous femoral nerve block provide adequate pain relief in patients undergoing anterior cruciate ligament reconstruction, whereas intra-articular analgesia seems unable to cope satisfactorily with the analgesic requirements of this surgical procedure.   

Gupta et al (2004) reported on the results of a randomized controlled clinical trial comparing continuous intra-peritoneal infusion of levobupivacaine versus normal saline placebo in 40 women undergoing elective abdominal hysterectomy.  The investigators found a reduction in opioid consumption in the levobupivacaine group lasting from 4 to 24 hours after surgery, which was associated with a reduced incidence of nausea.  Despite a reduction in analgesic requirement during this period with levobupivacaine infusion, patients had moderate pain during coughing, which the investigators concluded was "unsatisfactory."  In addition, no differences were found between the groups in other endpoints, including vomiting, time to eating, drinking, mobilizing, or home discharge.

Boss et al (2004) examined the effectiveness of continuous sub-acromial bupivacaine infusion in 42 patients undergoing acromioplasty and rotator cuff repair.  Patients were randomly assigned to sub-acromial continuous infusions of bupivacaine or saline (placebo).  The investigators reported no significant differences in supplemental opioid consumption by intravenous patient controlled analgesia, in anti-emetic use, or in subjective pain perception by VAS between the groups.  The investigators concluded that the continuous sub-acromial infiltration of bupivacaine anesthetic is ineffective in providing pain relief after rotator cuff repair and acromioplasty surgery.

Fredman et al (2001) reported on the analgesic efficacy of patient-controlled wound instillation of the analgesic bupivacaine in 50 patients undergoing major abdominal surgery.  Subjects were randomly assigned to either bupivacaine or sterile water.  The investigators found no significant differences between groups in the amount of rescue opioid requirements during the 24 hour study period.  The investigators reported that VAS for pain were similar between groups at rest, on coughing, and after leg raise.  The investigators concluded that bupivacaine wound instillation via patient controlled analgesia pump does not decrease pain or post-operative opioid requirements after abdominal surgery.

In a randomized study, Zieren et al (1999) compared the effect of repeated intra-lesional boluses of local anesthetic to oral analgesic in 104 patients undergoing tension-free inguinal hernia repair.  Patients were randomly assigned to post-operative repeated boluses of bupivacaine analgesic through a subcutaneous catheter or oral analgesic dipyrone administered 6, 12, and 24 hours after operation.  The investigators reported no significant differences between groups in absolute pain scores, course of pain, and the effects of analgesics.  There were no differences in duration of hospital stay between groups.  The investigators concluded that repeated intra-lesional boluses of local anesthetic did not result in better pain control than oral analgesics after tension-free inguinal hernia repair.

Schurr et al (2004) evaluated post-operative continuous wound infusion of the local anesthetic bupivacaine to saline placebo in patients undergoing inguinal herniorrhaphy.  The investigators reported that patients ho received bupivacaine had lower ratings for worst pain than patients who received saline.  On day 1, least pain ratings were lower in patients receiving bupivacaine, and patients ambulated more frequently than those who received placebo.  However, these differences did not persist beyond the first post-operative day, and there were no differences between groups between post-operative days 2 through 5.  The investigators also reported no differences between groups in rescue narcotic consumption.  The investigators concluded that continuous infusion of local anesthetic after inguinal herniorrhaphy provided "modest" improvements in pain scores and functional outcomes when compared with placebo.  However, the investigators noted that these effects were limited to the first post-operative day only.

Bianconi et al (2003) reported on the results of a randomized trial comparing intravenous infusion of morphine plus ketorolac to continuous wound infusion of the anesthetic ropivicaine in 37 patients undergoing hip or knee joint replacement surgery.  The investigators reported that the group receiving the continuous wound instillation of had less post-operative pain at rest and on mobilization, less use of rescue medication, and a shorter hospital stay, than the group receiving intravenous analgesics.  However, the intravenous medication was discontinued after 24 hours, while the continuous wound instillation was continued for 55 hours.  The investigators noted that this was the only study of continuous wound instillation of local anesthetic after hip or knee arthroplasty, and that further studies may be necessary to confirm the efficacy of this new pain management strategy.

Rosseland et al (2004) reported that pain after knee arthroscopy is modest and short-lived and can successfully be treated with intra-articular saline as placebo in a randomized controlled study (n = 60).  In this study, 60 patients who developed moderate-to-severe pain after knee arthroscopy were randomly assigned to infusion of either 10 ml or 1 ml of intra-articular saline.  The investigators reported that pain intensity remained low and use of rescue medication and other pain outcome measures were similar during the 36-hour outcome period.  The investigators found that patients experienced equally good pain relief after intra-articular injection of saline.  The investigators concluded that this finding of a major placebo effect of intra-articular saline has implications for the interpretation of previously published placebo-controlled intra-articular analgesia studies.

Barber and Herbert (2002) reported on a randomized controlled clinical study of 50 consecutive patients undergoing arthroscopic shoulder surgery who were randomly assigned to either a saline or anesthetic solution via an infusion pump following surgery.  Although subjects assigned to anesthetic had lower pain scores than subject assigned to saline, there was no statistically significant difference between groups in use of post-operative oral medication.  Functional outcome measures were not assessed in this study. 

Harvey et al (2004) reported on a randomized, controlled clinical study of 24 patients undergoing arthroscopic sub-acromial decompression, 19 of whom completed the study.  Subjects were randomly assigned to continuous sub-acromial infusions of either anesthetic or saline.  Subjects assigned to anesthetic had less pain than subjects assigned to saline.  However, there were no significant differences between groups in the amount of supplemental hydrocodone consumption.  Functional outcome measures were not assessed in this study.    

Savoie et al (2000) reported on 62 consecutive patients undergoing arthroscopic subacromial decompression who were randomized to receive continuous intra-lesional infusions of either anesthetic or saline post-operatively.  Subjects assigned to anesthetic infusion reported modest but statistically significant reductions in pain scores post-operative days 1 through 5.  Subjects assigned to anesthetic infusion also had less use of supplemental narcotics.  Functional outcomes were not assessed.

A study by Gottschalk et al (2003) examined the effectiveness of continuous intra-lesional anesthetic infusion in 45 patients undergoing shoulder surgery.  Subjects were assigned to 3 groups: group 1 received a single dose wound infiltration of saline plus continuous post-operative wound infiltration with saline; groups 2 and 3 received a single dose wound infiltration with anesthetic, plus continuous post-operative wound infiltration with either lower dose or higher dose anesthetic.  Because of the design of this study, one can not discern the contributions of single dose wound infiltration and post-operative continuous wound infiltration to outcomes.  Post-operative pain was less in the group receiving higher dose anesthetic than lower dose anesthetic or saline during the 48 hour duration of the study.  Cumulative supplemental analgesic consumption was less in the subjects receiving intra-lesional anesthetic.  Functional outcomes were not assessed.

Klein et al (2003) compared the effectiveness of inter-scalene brachial plexus block followed by continuous intra-articular infusion to inter-scalene brachial plexus block followed by continuous inter-scalene infusion in 17 patients who were undergoing outpatient rotator cuff repair.  The investigators reported similarly high VAS scores at rest and with movement and similarly high narcotic consumption between the 2 groups.  The investigators noted that, overall, between 50 % and 70 % of all patients reported suboptimal analgesia, and that neither group was consistently able to achieve satisfactory analgesia (VAS less than 2) with supplemental oral narcotics.  The investigators concluded that "[t]he high VAS scores and need for additional medical care suggest that intra-articular administration may not be reasonable for this magnitude of surgery."

Klein et al (2001) examined the effects of intra-articular analgesia with a continuous infusion of local anesthetic in 40 patients undergoing shoulder arthroscopy.  Patients were randomly assigned to post-operative intra-articular infusion of anesthetic or saline.  Subjects assigned to anesthetic had lower post-operative pain scores and less consumption of supplemental narcotics.  Functional measures were not assessed.   

A study by Lau et al (2001) of 44 persons undergoing inguinal hernia repair is of weaker design because it is non-blinded with no sham infusion pump treatment given to the control group.  The investigators reported significant differences in pain scores in favor of the pump group lasting through the first day following surgery.  They also reported none of the 20 subjects assigned to intra-lesional infusion pumps required analgesics, compared to 6 of 24 subjects in the control group.  Because of the unblinded nature of this study, it is uncertain whether these differences may be attributable to placebo effects.  There were no differences between groups in post-operative recovery, including time to resume ambulation, time to resume voiding, and return to normal activities.  The investigators reported that the main drawbacks to the use of an intra-lesional pump were its high cost and the frequent seepage of blood-stained anesthetic fluid into the wound dressing, which occurred in a quarter of subjects assigned to intra-lesional anesthetic pumps.

A study by Cheong et al (2001) of 70 persons undergoing laparotomy for major colorectal surgery is also non-blinded.  Patients were randomly assigned to patient-controlled analgesia (PCA) or to intra-lesional anesthesia.  The investigators reported that there was no statistically significant difference in post-operative pain scores at rest and with movement between the 2 groups, except the first post-operative day, where the median pain scores in the intra-lesional anesthesia group were higher than those in the PCA group.  The investigators reported that the median amount of morphine used was significantly greater in the subjects assigned to PCA than in subjects assigned to intra-lesional anesthesia.  This difference may be attributable to the non-blinded nature of this study and the fact that subjects assigned to PCA could self-administer morphine on demand, whereas subjects assigned to intra-lesional anesthesia had to request morphine administered via a subcutaneous injection.  The investigators noted that none of the patients in either group was unduly sedated or confused owing to either form of analgesia during the study.  The investigators reported no significant differences in time to return of bowel movement, time to post-operative mobilization, and time to discharge from hospital.  It should be noted that 4 patients in the intra-lesional anesthesia group developed wound infection, compared to 1 patient in the PCA group.  

A study by Morrison and Jacobs (2003) is also of weaker design in that it is non-blinded, non-randomized retrospective consecutive case series of 49 mastectomy patients treated over a 5-year period, with comparisons before and after introduction of intra-lesional anesthetic infusion pumps.  Factors other than the use of an intra-lesional infusion pump (e.g., improvements in surgical techniques, rehabilitation protocols, etc.) may have accounted for differences in use of post-operative pain medication, length of hospital stay, and post-operative stay in post-anesthesia care unit (PACU) before and after they began using intra-lesional anesthetic pumps at the study institution.

A study by Chew et al (2003) is of weaker design than many of the previously described studies in that it is a non-randomized study that uses historical controls rather than randomly assigned concurrent controls. 

A study by Mallon et al (2000) is of weaker design in that it compares intra-articular anesthetic infusion to no infusion, and hence the study is non-blinded and lacks a placebo control group.  Studies by Rawal et al (1997), Ganapathy et al (2000) and Crawford et al (1997) are of weaker design in that they lack a control group.  A study by Yamaguchi et al (2002) is a report of a retrospective, uncontrolled case series.  A study by Vintar et al (2002) compared intra-lesional bupivacaine to intra-lesional ropivacaine in 60 patients who underwent inguinal hernia repair, and hence did not inform whether there are clinically significant benefits to the administration of intra-lesional anesthesia. 

Several studies after total knee arthroplasty (Klasen et al, 1999; Schwarz et al, 1999; Rautoma et al, 2000; DeWeese et al, 2001) and other surgical procedures (Adams et al, 1991; Forgach and Ong, 1995) have concluded that application of intra-articular or intra-lesional local anesthetics and/or morphine does not reduce analgesic requirements, and there have been no studies to prove beneficial effects on post-operative recovery and rehabilitation.

Nechleba et al (2005) examined the effectiveness of local, continuous infusion of bupivacaine for pain control following total knee arthroplasty.  A total of 11 men and 19 women with an average age of 65 years (range of 43 to 83 years) randomly received either 0.25 % bupivacaine or normal saline by local infusion pump.  Standard wound drainage also was implemented.  Pain was assessed with a VAS along with patient-controlled analgesia demand, narcotic delivery, and NSAID administration.  Drug lost to drainage also was assessed.  Mean pre-operative VAS were similar between the saline and bupivacaine groups (6.5 +/- 1.4 and 6.1 +/- 2.0, respectively; p = 0.535).  By the end of the second post-operative day, scores decreased to 3.4 +/- 3.2 for the saline group and 2.5 +/- 1.6 for the bupivacaine group.  Although post-operative reductions were statistically significant (p = 0.007), the main treatment effect was not (p = 0.404).   Mean narcotic demand and usage were 87 +/- 114.1 requests with usage of 11.8 +/- 12.3 mg for the saline group and 96 +/- 104.8 requests with usage of 7.5 +/- 3.8 mg for the bupivacaine group (p = 0.505).  Cumulative ketorolac administration was 47 +/- 52.2 mg for the saline group and 83.6 +/- 64.9 mg for the bupivacaine group (p = 0.100).  Hydrocodone-acetaminophen usage also was similar between the saline and bupivacaine groups (88 +/- 43.9 mg and 64.6 +/- 35 mg, respectively) (p = 0.112).  Drug lost to drainage was estimated to be 27 %.  These investigators concluded that their findings suggested continuous local analgesic infusion after total knee arthroplasty does not offer significant improvements in either pain relief or medication use.  Drug loss from drainage may exceed 25 % and may compromise analgesic effectiveness.

Other recently published studies also demonstrate the inconsistencies in results of intralesional and intra-articular anesthetic pumps (Wu et al, 2005; Kushner et al, 2005; Morgan et al, 2006; Baig et al, 2006; Parker et al, 2007).  In a prospective, double-blind, placebo-controlled, randomized study, Wu et al (2005) examined if a sub-fascial continuous infusion of local anesthetic in patients undergoing radical retropubic prostatectomy would result in a reduction in post-operative opioid requirements and an improvement in pain scores.  A small catheter was placed sub-fascially at the end of the operation and attached to an elastomeric pump, which administered either 0.5 % bupivacaine or normal saline into the wound at a rate of 2 ml/hour until discharge on post-operative day 3.  The outcomes assessed included the dosage of hydromorphone used by a patient-controlled analgesic system, a VAS for pain at rest and with activity, a VAS of nausea, and length of hospital stay.  A total of 100 patients were successfully randomized, with all patients completing the protocol.  No differences were found between the groups with regard to VAS pain at rest, VAS pain with activity, intravenous or oral analgesic consumption, or VAS nausea scores.  The authors concluded that continuous sub-fascial infusion of local anesthetic did not result in a post-operative reduction in opioid requirements or an improvement in pain scores in patients undergoing radical retropubic prostatectomy.

Continuous local anesthetic infusion has also been employed at the iliac crest bone graft (ICBG) site following spinal arthrodesis.  Singh et al (2005) examined the effects of post-operative continuous local anesthetic agent infusion at the ICBG harvest site in reducing pain, narcotic demand and usage, and improving early post-operative function after spinal fusion.  A total of 37 patients were enrolled in a prospective, randomized, double-blind, parallel-designed study (28 had ICBG harvested for lumbar arthrodesis and 9 for cervical arthrodesis).  During spinal arthrodesis surgery, patients were randomly assigned to receive 96 ml (2 ml/hour x 48 hours) of either normal saline (control group, n = 22) or 0.5 % Marcaine (treatment group, n = 15) delivered via a continuous infusion catheter placed at the ICBG harvest site.  All patients received dilaudid patient-controlled analgesia after surgery.  Pain scores, narcotic use/frequency, activity level, and length of stay (LOS) were recorded.  Physicians, patients, nursing staff, and statisticians were blinded to the treatment.  Mean patient age was 60 years and similar between groups.  Narcotic dosage, demand frequency, and mean VAS pain score were significantly less in the treatment group at 24 and 48 hours (p < 0.05).  The average LOS was 4.1 days with no difference between the treatment group (4.3 days) and the control (group 3.9 days).  No complications were attributed to the infusion-catheter system.  The authors concluded that continuous infusion of 0.5 % Marcaine at the ICBG harvest site reduced post-operative parenteral narcotic usage by 50 % and decreased overall pain scores.  No complications were attributed to the infusion-catheter system.  They noted that the use of continuous local anesthetic infusion at the iliac crest may help in alleviating acute graft-related pain, hastening patient recovery and improving short-term satisfaction.  This is in agreement with the findings of Cowan et al (2002) who stated that administration of local anesthetic is a safe and effective technique for pain relief at the iliac crest donor site in patients who have undergone cervical fusion (n = 14).

In contrast to the findings by Cowan et al (2002) and Singh et al (2005), Morgan and colleagues (2006) reported that continuous infusion of bupivacaine at ICBG sites during the post-operative period is not an effective pain control measure in hospitalized patients receiving systemic narcotic medication.  In a prospective, double-blind, randomized clinical trial, Morgan et al (2006) examined if continuous infusion of 0.5 % bupivacaine into the iliac crest harvest site provides pain relief that is superior to the relief provided by systemic narcotic pain medication alone in patients undergoing reconstructive orthopedic trauma procedures.  Patients (over 18 years of age) were randomized to the treatment arm (bupivacaine infusion pump) or the placebo arm.  Post-operatively, all subjects received morphine sulfate with use of a patient-controlled analgesia pump.  Subjects recorded the pain at the donor and recipient sites with use of a scale ranging from 0 to 10.  The use of systemic narcotic medication was recorded.  Independent-samples t tests were used to assess differences in perceived pain relief between the treatment and control groups at 0, 8, 16, 24, 32, 40, and 48 hours after surgery.  Pain was also evaluated at 2 and 6 weeks post-operatively.  A total of 60 patients were enrolled.  Across all data points, except pain at the recipient site at 24 hours, no significant differences in the perception of pain were found between the bupivacaine group and the placebo group.  It is interesting to note that on the average, patients in the treatment group reported more pain than those in the control group.  No significant difference was found between the 2 groups with regard to the amount of narcotic medication used.  The authors concluded that no difference in perceived pain was found between the groups.  The results of this study indicated that continuous infusion of bupivacaine at ICBG sites during the post-operative period is not an effective pain-control measure in hospitalized patients receiving systemic narcotic medication.  This is in agreement with the observation of Puri et al (2000) who stated that in view of the lack of improvement in pain relief and the risk of infection, local administration of bupivacaine at the iliac bone harvest site following cervical diskectomy/foot arthrodesis (n = 13) is not recommended for post-operative analgesia.

Polglase et al (2007) reported on a lack of efficacy of a continuous wound infusion of ropivacaine in conjunction with best practice post-operative analgesia after midline laparotomy for abdominal colorectal surgery.  The investigators performed a randomized, participant and outcome assessor-blinded, placebo-controlled trial on patients presenting for major abdominal colorectal surgery.  Subjects were allocated to receive ropivacaine 0.54 % or normal saline via a dual catheter Painbuster Soaker continuous infusion device into their mid-line laparotomy wound for 72 hours post-operatively.  A total of 310 patients were included in this study.  The investigators found that the continuous wound infusion of ropivacaine after abdominal colorectal surgery conveys minimal benefit compared with saline wound infusion.  The investigators found no statistically significant difference for: pain at rest, morphine usage, length of stay, mobility, nausea, or return of bowel function.  There was a small, statistically significant difference in mean pain on movement on day 1 for the ropivacaine group (adjusted mean difference -0.6 (range of -1.08 to -0.13)).  The investigators reported that, although this trend continued on days 2 and 3, the differences between groups were no longer statistically significant.  The investigators concluded that delivery of ropivacaine to midline laparotomy wounds via a Painbuster Soaker device did not demonstrate any significant clinical advantage over current best practice.

Liu et al (2006) conducted a systematic evidence review of intra-lesional and intra-articular anesthetic pumps.  The authors stated that they were motivated to conduct a systematic review of continuous wound catheters delivering local anesthetic because "there have been conflicting reports of the overall efficacy, and no single, large randomized control trial (RCT) has definitively assessed the risk of this modality."  Available randomized controlled clinical studies of continuous wound catheters are small considering the size of the eligible population.  A primary problem with this systematic review is that it inappropriately combined studies involving heterogenous patient populations, anesthesia indications, catheter placement, and methods of continuous infusion in its overall and subgroup analyses.  The authors noted that future large homogenous randomized controlled trials would be valuable to verify the findings of the systematic review and provide better quantitative data.  In addition, the authors stated that they were not able to answer basic questions, including cost-effectiveness, site of catheter placement, or dosage, because of the variability among studies.

It remains unclear whether any analgesia produced by intra-articular and intra-lesional anesthetics is clinically useful.  Estimates of the impact of intra-lesional and intra-articular anesthetic pumps on duration of hospitalization were based upon very few studies.  Few studies have examined the impact of intra-articular and intra-lesional anesthetic pumps on functional outcomes (reductions in disability, improvements in function, or faster recovery).  In addition, few studies have directly compared the effectiveness and safety of intra-articular or intra-lesional infusions with established methods of post-operative analgesia (Tran et al, 2005).  Finally, available studies are small and not sufficiently powered to evaluate uncommon but clinically significant adverse effects of intra-lesional and intra-articular catheters (Hoeft et al, 2006).

In a retrospective study, Bray and colleagues (2007) evaluated the effectiveness of a local anesthetic pain infusion pump in the management of post-operative pain in abdominoplasty patients.  A total of 38 abdominoplasty patients with local anesthetic pain pumps and 35 abdominoplasty patients without pain pumps were included in this study.  Pain pumps were loaded with 0.25 % or 0.5 % bupivacaine and infused at a constant rate of 4 ml/hour.  All patients were admitted post-operatively and started on a narcotic PCA.  Post-operative PCA narcotic use and pain scores were recorded every 2 hours by the nursing staff.  For the first 24 hours of post-operative hospital stay, pain medication, pain scores, and anti-emetic use were determined from the patients' charts.  Hospital stay was also reviewed.  In the pain pump group, there was a small but statistically non-significant reduction in pain medication use (2.65 versus 3.04 pain units) (p = 0.34).  Interestingly, pain scores were higher in the pain pump group but not significantly (2.73 versus 2.31) (p = 0.17).  There was no statistically significant difference in the use of anti-emetics (0.8 versus 0.6) (p = 0.60).  Hospital length of stay averaged 2.2 days in the pain pump group and 2.5 days in the group without pain pumps (p = 0.09).  The authors concluded that the post-operative use of pain pumps in abdominoplasty patients does not significantly improve pain management.  They stated that further investigation into this application of the pain pump is necessary before recommending their routine use in abdominoplasty patients.

Charous (2008) stated that management of post-operative pain can be critical to the success of a patient's recovery following head and neck surgery.  Various medications and delivery methods have been tried to maximize patients' comfort while minimizing many of the medications' potential side effects.  Continuous wound perfusion pain management systems are being used in various surgical specialties.  In a preliminary report, the author described the use of one such pain management system (On-Q) in thyroid and parotid surgeries.  Statistically significant less levels of pain, use of opioids and nausea/vomiting were noted in patients who used the On-Q system.  There were no complications.  The author concluded that the use of the On-Q system in various head and neck procedures is promising; further research, evaluation, and exploration of its possible uses are encouraged.

In a prospective, randomized, double-blind, controlled trial, Kazmier et al (2008) examined the effectiveness of the pain pump after cosmetic breast augmentation.  A total of 25 women were enrolled in the study; 5 were eliminated from analysis because of data inadequacy or device problems.  After bilateral augmentation, the remaining 20 patients received a 4-day continuous infusion of bupivacaine in one breast pocket and saline in the other.  Laterality of bupivacaine infusion was randomized and blinded to both the patient and the surgeon.  Patients completed a questionnaire on post-operative days 1, 2, 3, 4, and 7, rating their pain on a scale of 0 to 10, with 10 being worst.  On post-operative day 1, the mean pain score was 4.7 on the bupivacaine side versus 5.4 on the saline side (p = 0.36).  On post-operative days 2, 3, 4, and 7, the mean scores were 4.3 versus 4.6 (p = 0.63), 3.3 versus 3.8 (p = 0.50), 3.4 versus 3.6 (p = 0.78), and 3.4 versus 3.1 (p = 0.63) for the bupivacaine and saline sides, respectively.  The authors concluded that the pain pump appears to provide breast augmentation patients marginal improvement in pain control, although this advantage did not reach statistical significance in this study.  The benefit, if real, also appears to wane over the first post-operative week.

An assessment by the Galacian Agency for Health Technology Assessment (AVALIA-T) (Acevedo Prado and Atenzio Merino, 2008) found no clear evidence of improved outcomes with continuous anesthetic infusion pumps versus other methods of managing post-operative pain.  The assessment identified 10 clinical trials that met pre-specified inclusion criteria.  The investigators found that, in general, the results of these clinical trials did not consistently favor continuous anesthetic infusion pumps over standard methods of postoperative pain management.  The assessment found that, in some of the clinical trials, there was a slight improvement in pain scores or reductions requirements for narcotic analgesics, but other studies found no such differences.  One difficulty in interpreting studies that was noted in the assessment is the lack of common methodology in clinical trials.

An assessment by IECS (Tapia-López, et al., 2016) stated that scarce and low-quality evidence has shown no additional clinical benefit of elastomeric pumps over other delivery devices in hospitals analgesics for pain management. Evidence for the infusion of other drugs such as chemotherapeutic agents, antibiotics, antivirals and chelating is insufficient. No studies comparing the use of elastomeric pumps in the outpatient setting against other devices in hospitals were found.

In a randomized, placebo-controlled, double-blind study, Chen et al (2010) examined if continuous intra-articular infusion of bupivacaine via pain-control infusion pumps (PCIP) enhances and sustains analgesia after total hip arthroplasty (THA).  A total of 92 patients undergoing THA were randomized to receive continuous intra-articular infusion of either 0.5 % bupivacaine or 0.9 % normal saline at a flow rate of 2 ml/hr via a PCIP for 48 hrs.  The primary outcome measure was pain intensity on VAS scores in the first 72 hrs.  Other measures included time to first rescue dose of narcotics, amount of narcotic use, presence of adverse events, length of hospital stay, and hip function evaluated with the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index.  Despite a longer time to first narcotic rescue (56 mins versus 21 mins, p < 0.0001) in patients receiving bupivacaine, the 2 groups did not differ significantly in overall pain relief (p = 0.54).  A lower VAS score was found only at time 0-hr and 2-hr; no difference in VAS score was noted at any other time point.  Additionally, no difference was found in terms of amount of narcotic use, incidence of adverse events, hospitalization days, and the WOMAC score.  The authors concluded that continuous intra-articular infusion of 0.5 % bupivacaine at 2 ml/hr via a PCIP does not provide sustained post-operative pain relief in patients undergoing THA.

In a prospective, randomized study, Jarvela and Jarvela (2008) evaluated the long-term effect of the use of a pain pump after arthroscopic sub-acromial decompression.  A total of 50 patients were included in this study (25 had a 24-hr pain pump with 0.375 % ropivacaine infusion and a continuous rate of 5 ml/hour in the sub-acromial space after arthroscopic sub-acromial decompression, and 25 did not).  Rehabilitation was similar in both groups.  Evaluation methods were clinical examination, radiographical evaluation, and isometric elevation strength measurements, as well as the University of California, Los Angeles and Constant shoulder scores.  All the operations were done by 1 experienced orthopedic surgeon, and all the evaluations at follow-up were done by 1 independent, blinded examiner.  There were no differences between the study groups pre-operatively.  Of the patients, 47 (94 %) were available at a minimum follow-up of 2 years (range of 24 to 32 months).  Concerning the duration of sick leave (p = 0.053) and ability to return to work (p = 0.321), the group differences were not statistically significant.  At follow-up, the shoulder scores (University of California, Los Angeles and Constant) were significantly better than pre-operatively (p < 0.001) in both groups, although no differences were found between the groups.  The isometric elevation strengths of the operated shoulders were equally good in both groups (p = 0.976) as well, and no significant differences were observed between the operated shoulders and non-operated shoulders at follow-up.  The authors concluded that the use of a pain pump after arthroscopic subacromial decompression did not have any long-term effects on the patients' recovery, return to work, or final result at the minimum 2-year follow-up.

In a randomized, participant and outcome assessor-blinded, placebo-controlled study, Coghlan et al (2009) examined the safety and effectiveness of ropivacaine infusion following arthroscopic or mini-incision rotator cuff surgery.  Subjects, stratified by operative procedure (either arthroscopic decompression or rotator cuff repair), were given preemptive 1 % ropivacaine (20 ml) and intra-operative intravenous parecoxib (40 mg) and were randomly assigned to 0.75 % ropivacaine or placebo by elastomeric pump at 5 ml/hr.  Pain at rest was reported on a verbal analog scale at 15, 30, and 60 mins and at 2, 4, 8, 12, 18, and 24 hrs.  The use of alternative analgesia, delay in discharge, and adverse events, including development of stiff painful shoulder, infection, and leakage, were also assessed.  A total of 84 participants received arthroscopic decompression (43 in the placebo arm and 45 in the ropivacaine arm) and 70 received rotator cuff repair (35 participants in each treatment arm).  Compared with placebo, ropivacaine infusion resulted in a significant but clinically unimportant improvement in average pain in the first 12 hours following both procedures (the average pain score was 1.62 and 2.16 for the ropivacaine and placebo arms, respectively, in the arthroscopic decompression group and 2.12 and 2.82 in the rotator cuff repair group, with a pooled difference between groups of 0.61; 95 % confidence interval [CI]: 0.22 to 1.01; p = 0.003).  When adjusted for opioid use, the pooled difference between groups was 0.49 (95 % CI: 0.12 to 0.86; p = 0.009).  No difference was detected between groups with regard to the maximum pain in the first 12 hrs or the average or maximum pain in the second 12 hrs, with or without adjustment for opioid use, and no difference was found between groups with regard to the amount of oral analgesia used.  No difference was detected between groups with regard to the prevalence of nausea and vomiting, catheter leakage, delayed discharge, or stiff painful shoulder, and no subject in either group developed post-operative infection.  The authors concluded that there was minimal evidence to support the use of ropivacaine infusion for improving outcomes following rotator cuff surgery in the setting of preemptive ropivacaine and intra-operative parecoxib.

There is emerging evidence of a relationship between intra-articular administration of chondrotoxic anesthetics and post-arthroscopic glenohumoral chondrolysis (McNickle et al, 2009; Busfield et al, 2009; Saltzman et al, 2009; Bailie et al, 2009; Hansen et al, 2007; Gomoll et al, 2006).  Chondrolysis is characterized by the complete loss of articular (or hyaline) cartilage, and is usually irreversible.  The chondrotoxic effects of anesthetics bupivacaine and epinephrine are thought to lead to cartilage damage.

At the request of the ORM subcommittee of the American Academy of Orthopedic Surgeons Medical Liability Committee, Morrell (2008) presented a paper on the use of intra-articular continuous infusion pumps and chondrotoxicity.  The author stated that ideal post-operative analgesic protocol is one that results in the optimal control of pain with the least exposure to side effects and risk of complications.  Although continuous infusion systems offer a certain degree of convenience, the ideal delivery system and agent for intra-articular infusions have yet to be defined.  Furthermore, surgeons should not discount the value of pain, because pain is often the first sign of an impending complication, and continuous infusion of local anesthetics into a surgical site may mask that warning.

In a retrospective chart review, Andersen et al (2010) reported their experience of patients who received infusion of bupivacaine with epinephrine after arthroscopic glenoid labral repair surgery and in whom glenohumeral joint chondrolysis subsequently developed, and determined the incidence of such chondrolysis in their patient populations.  A total of 18 patients diagnosed with chondrolysis was included in this study.  All patients were from 2 experienced orthopedic surgeons' practices.  Details of their clinical course were obtained and summarized.  These data were compared with all other arthroscopies completed by the 2 surgeons to determine the incidence of chondrolysis.  All 18 patients diagnosed with glenohumeral joint chondrolysis received post-operative infusion of bupivacaine with epinephrine through an intra-articular pain pump catheter (IAPPC).  None of the patients received thermal energy as part of their procedure.  None of the patients had evidence of glenohumeral joint infection, although an extensive work-up was frequently undertaken.  Clinically, patients presented with a stiff, painful shoulder. Examination showed decreased range of motion of the affected shoulder.  Radiographs and magnetic resonance imaging showed joint space narrowing, as well as subchondral sclerosis and cyst formation. Of the 18 patients, 14 had since undergone repeat arthroscopic procedures, and 5 have received a humeral head-resurfacing operation.  Within the same time period, there were 113 arthroscopies, with 45 pain pumps used.  Chondrolysis developed in 16 of 32 patients with high-flow IAPPCs and 2 of 12 patients with low-flow IAPPCs (1 patient's IAPPC flow rate was not documented).  The authors concluded that although they can not establish a causal link, the development of glenohumeral chondrolysis may be related to the intra-articular infusion of bupivacaine with epinephrine post-operatively.  Thus, they caution against the use of IAPPCs.

Chen et al (2010) examined if continuous intra-articular infusion of bupivacaine via pain-control infusion pumps (PCIP) enhances and sustains analgesia after total hip arthroplasty (THA).  A total of 92 patients undergoing THA were randomized to receive continuous intra-articular infusion of either 0.5 % bupivacaine or 0.9 % normal saline at a flow rate of 2 ml/hr via a PCIP for 48 hrs.  The primary outcome measure was pain intensity on VAS scores in the first 72 hrs.  Other measures included time to first rescue dose of narcotics, amount of narcotic use, presence of adverse events, length of hospital stay, and hip function evaluated with the WOMAC index.  Despite a longer time to first narcotic rescue (56 versus 21 mins, p < 0.0001) in patients receiving bupivacaine, the 2 groups did not differ significantly in overall pain relief (p = 0.54).  A lower VAS score was found only at time 0 and 2 hrs; no difference in VAS score was noted at any other time point.  Additionally, no difference was found in terms of amount of narcotic use, incidence of adverse events, hospitalization days, and the WOMAC score.  The authors concluded that continuous intra-articular infusion of 0.5 % bupivacaine at 2 ml/hr via a PCIP does not provide sustained post-operative pain relief in patients undergoing THA.

Gottschalk and Gottschalk (2010) noted that continuous wound infusion of local anesthetics, which is mainly used in general surgery and orthopedics, is an interesting technique in post-operative pain therapy.  Continuous wound infusion of local anesthetics is able to reduce post-operative opioid requirements and results in decreased pain scores.  Recent studies indicate that rehabilitation seems to be enhanced and post-operative hospital stay may be shorter.  Continuous wound infusion is an effective analgesic technique, which is simple to perform.  Moreover, the authors stated that comparisons with other analgesic techniques (e.g., peripheral nerve blocks, epidural analgesia and other multi-modal analgesic concepts) are still needed.

Scheffel et al (2010) reviewed the literature on glenohumeral chondrolysis to test the hypothesis that common factors could be identified and that the identification of these factors could suggest strategies for avoiding this complication.  These investigators identified 16 articles reporting 100 shoulders in which post-surgical glenohumeral chondrolysis had developed.  The average reported patient age was 27 +/- 11 years at the time of surgery; 35 were women.  The most common indications for surgery were instability (n = 68) and superior labrum antero-posterior lesions (n = 17).  In 59 cases, chondrolysis was reported to be associated with the use of intra-articular pain pumps.  The infusate was known to include bupivacaine in 50 shoulders and lidocaine in 2.  Radiofrequency capsulorrhaphy was performed in 2 shoulders.  Overall, 59 % of the reported cases of glenohumeral chondrolysis occurred with the combination of arthroscopic surgery and post-arthroscopy infusion of local anesthetic.  The arthroscopic operations observed with chondrolysis were not limited to stabilization procedures, and the infused anesthetic was not limited to bupivacaine.  The authors concluded that post-operative infusion of local anesthetic and radiofrequency may not be essential to the success of shoulder arthroscopy, surgeons may wish to consider the possible risks of their use.

Furthermore, the FDA (2010) has reviewed 35 reports of chondrolysis in patients who received continuous intra-articular infusions of local anesthetics with elastomeric infusion devices (pain pumps) for post-operative pain management.  The local anesthetics involved entail bupivacaine, chloroprocaine, lidocaine, mepivacaine, procaine, as well as ropivacaine with and without epinephrine.  The FDA stated that the significance of this injury to otherwise healthy young adults warrants notification to health care professionals.  The FDA is requiring the drug manufacturers to update their product labels to warn healthcare professionals about this potential serious adverse effect.  It is also exploring possible options for addressing the safety issues with the infusion devices.

In a recent review on the treatment of acute post-operative pain, Wu and Raja (2011) stated that one concern with the infusion of local anesthetics intraarticularly is the association of this technique with catastrophic chrondrolysis.

In a double-blind, placebo-controlled study, Baulig et al (2011) quantified the impact of continuous wound infusion with ropivacaine 0.33 % on morphine administration and subjective pain relief in patients after open abdominal aortic repair.  Before closing the abdominal wound, 2 multi-hole ON-Q^® Soaker Catheters™ (I-Flow Corporation, Lake Forest, CA) were placed pre-peritoneally in opposite directions.  Either ropivacaine 0.33 % or saline 0.9 % was delivered by an elastomeric pump at a rate of 2 ml/hr for 72 hrs in each of the catheters.  Post-operative pain and morphine administration were assessed using the numerical rating scale (NRS) in 4-hr intervals.  Total plasma concentrations of ropivacaine, unbound ropivacaine, and alpha-1-acid glycoprotein (AAG) were measured daily.  Mean arterial pressure, pulse rate, oxygen saturation, total amount of morphine administration, ventilation time, and length of stay in the intensive care unit (ICU) were recorded.  At the end of the study period, the wound site and the condition of the catheters were assessed.  The study was terminated prematurely due to a malfunction of the elastomeric balloon pump resulting in toxic serum levels of total ropivacaine in 2 patients (11.4 μmol/L and 10.0 μmol/L, respectively) on the second post-operative day.  Six patients had been allocated to the ropivacaine group, and 9 patients had been allocated to the control group.  Demographic and surgical data were similar in both groups.  During the first 3 post-operative days, no difference between the ropivacaine and the control group was found in NRS (p = 0.15, p = 0.46, and p = 0.88, respectively) and morphine administration (p = 0.48).  Concentrations of unbound serum ropivacaine (0.11 +/- 0.08 μmol/L) were below toxic level in all patients.  The authors concluded that continuous wound infusion of ropivacaine 0.33 % 2 ml/hr using an elastomeric system was not reliable and did not improve post-operative pain control in patients after open abdominal aortic surgery.

Ilfeld (2017) noted that a CPNB consists of a percutaneously inserted catheter with its tip adjacent to a target nerve/plexus through which local anesthetic may be administered, providing a prolonged block that may be titrated to the desired effect.  The current update is an evidence-based review of the CPNB literature published in the interim.  Novel insertion sites include the adductor canal, inter-pectoral, quadratus lumborum, lesser palatine, ulnar, superficial, and deep peroneal nerves.  Noteworthy new indications include providing analgesia after traumatic rib/femur fracture, manipulation for adhesive capsulitis, and treating abdominal wall pain during pregnancy.  The preponderance of recently published evidence suggested benefits nearly exclusively in favor of catheter insertion using ultrasound (US) guidance compared with electrical stimulation, although little new data are available to help guide practitioners regarding the specifics of US-guided catheter insertion (e.g., optimal needle-nerve orientation).  After some previous suggestions that automated, repeated bolus doses could provide benefits over a basal infusion, there is a dearth of supporting data published in the past few years.  An increasing number of disposable infusion pumps does now allow a similar ability to adjust basal rates, bolus volume, and lockout times compared with their electronic, programmable counterparts, and a promising area of research is communicating with and controlling pumps remotely via the Internet.  Large, prospective studies now document the relatively few major complications during ambulatory CPNB, although RCTs demonstrating an actual shortening of hospitalization duration are few.  Recent evidence suggested that, compared with femoral infusion, adductor canal catheters both induce less quadriceps femoris weakness and improve mobilization/ambulation, although the relative analgesia afforded by each remains in dispute.  Newly published data demonstrated that the incidence and/or severity of chronic, persistent post-surgical pain may, at times, be decreased with a short-term post-operative CPNB.  Few new CPNB-related complications have been identified, although large, prospective trials provided additional data regarding the incidence of adverse events (AEs).  In addition, the authors noted a number of novel, alternative analgesic modalities are under development/investigation; and 4 such techniques were described and contrasted with CPNB, including single-injection PNBs with newer adjuvants, liposome bupivacaine used in wound infiltration and PNBs, cryoanalgesia with cryoneurolysis, and percutaneous peripheral nerve stimulation.

Zhang and colleagues (2017) performed a systematic review and meta-analysis of RCTs to evaluate the safety and effectiveness of local anesthetic infusion pump versus placebo for pain management following TKA.  In September 2016, a systematic computer-based search was conducted in the PubMed, ISI Web of Knowledge, Embase, Cochrane Database of Systematic Reviews; RCTs of patients prepared for primary TKA that compared local anesthetic infusion pump versus placebo for pain management following TKA were retrieved.  The primary end-point was VAS with rest or mobilization at 24, 48 and 72 hours and morphine consumption at 24 and 48 hours.  The secondary outcomes were range of motion (ROM), LOS, and complications (infection, deep venous thrombosis (DVT), prolonged drainage and post-operative nausea and vomiting (PONV)).  A total of 7 clinical studies with 587 patients were included and for meta-analysis.  Local anesthetic infusion pump were associated with less pain scores with rest or mobilization at 24 and 48 hours with significant difference.  However, the difference was likely no clinical significance.  There were no significant difference between the LOS, the occurrence of DVT, prolonged drainage and PONV.  However, local anesthetic infusion pump may be associated with more infection.  The authors concluded that based on the current meta-analysis, there is evidence to support the routine use of local anesthetic infusion pump in the management of acute pain following TKA.  They stated that more RCTs are needed to identify the pain control effects and optimal dose and speed of local anesthetic pain pump.

In an observational, prospective cohorts study, Ortega-Garcia and colleagues (2018) examined if post-operative continuous wound infiltration of levobupivacaine through 2 sub-muscular catheters connected to 2 elastomeric pumps after lumbar instrumented arthrodesis is more effective than intravenous PCA.  The VAS, the need for additional rescue analgesia and the onset of adverse effects were recorded.  Pain records measured with VAS were significantly lower in the 48 hours post-operative record at rest (p = 0.032).  The other records of VAS showed a clear tendency to lower levels of pain in the group treated with the catheters.  No statistically significant differences were found in the rescue analgesia demands of the patients.  The adverse effects were lower in the catheter group (6 cases versus 11 cases) but without statistical differences.  The authors concluded that a trend to lower pain records was found in the group treated with catheters, although differences were not statistically significant.

Anesthetic Infusion Pump Following Open Inguinal Hernia Repair

In a meta-analysis, Wu and colleagues (2014) evaluated the effectiveness of local anesthetic infusion pump following open inguinal hernia repair for the reduction of post-operative pain.  These researchers conducted a systematic review and meta-analysis of RCTs that have investigated the outcomes of using an infusion pump for delivering a local anesthetic contrasted to a control group for open inguinal hernia repair.  Pain was assessed from Day 1 to Day 5 following the surgery.  The secondary outcomes included analgesia use and post-operative complications.  These investigators reviewed 5 trials that totaled 288 patients.  The analgesic effects of bupivacaine (4 trials) and ropivacaine (1 trial) were compared with a placebo group.  The pooled mean difference in the score measuring the degree of pain diminished significantly at Day 1 to Day 4 in the experimental group.  Two studies have reported that the number of analgesics required also decreased in the experimental group.  No bupivacaine-related complication was reported.  The authors concluded that the findings of this study revealed that applying a local anesthetic infusion pump following inguinal hernia repairs was more effective for reducing post-operative pain than a placebo.  However, they stated that the findings were based on a small body of evidence in which methodological quality was not high.  They noted that the potential benefits of applying a local anesthetic infusion pump to hernia repair must still be adequately investigated using further RCTs.

Anesthetic Infusion Pump Following Bariatric Surgery

Cottam et al (2007) stated that the use of a bupivacaine pain pump has previously been reported to lower costs to hospitals, while providing similar pain relief to opioid-based patient controlled analgesia (PCA) pumps. However, these benefits have not been investigated in laparoscopic bariatric surgery.  These investigators prospectively randomized 40 laparoscopic Roux-en-Y gastric bypass (LRYGBP) patients into 2 groups.  The 1st group received the ON-Q bupivacaine pain pump placed sub-xiphoid and radiating in both directions caudally beneath the lowest rib.  The 2nd group was treated with a meperidine PCA, which was initiated in the post-anesthesia care unit (PACU) and discontinued at 06:00 hour the following morning.  Both groups had identical surgery, anesthesiologists, anesthesia protocol and post-operative nausea prophylaxis.  There were no significant differences between the groups with regard to age, sex, pain scores, nausea scores, gas pain scores, anti-emetic use throughout their stay, or opioid use in the PACU.  However, there was a dramatic decrease in opioid use between the 2 groups over the time interval from leaving the PACU to 06:00 hour (meperidine by PCA mean of 217 mg versus ON-Q 129 mg meperidine equivalents, p = 0.008).  The authors concluded that the use of a bupivacaine pain pump offered the opportunity to dramatically reduce the use of opioids post-operatively in all bariatric patients by eliminating PCA.  This change could potentially reduce the incidence of respiratory failure from over-sedation, while offering the same levels of pain control.

In a retrospective study, Bray et al (2007) evaluated the effectiveness of a local anesthetic pain infusion pump in management of post-operative pain in abdominoplasty patients. A total of 38 abdominoplasty patients with local anesthetic pain pumps and 35 abdominoplasty patients without pain pumps were included in this study.  Pain pumps were loaded with 0.25 % or 0.5 % bupivacaine and infused at a constant rate of 4 ml/hour.  All patients were admitted post-operatively and started on a narcotic PCA.  Post-operative PCA narcotic use and pain scores were recorded every 2 hours by the nursing staff.  For the 1st 24 hours of post-operative hospital stay, pain medication, pain scores, and anti-emetic use were determined from the patients' charts.  Hospital LOS was also reviewed.  In the pain pump group, there was a small but not statistically significant reduction in pain medication use (2.65 versus 3.04 pain units) (p = 0.34).  Interestingly, pain scores were higher in the pain pump group but not significantly (2.73 versus 2.31) (p = 0.17).  There was no statistically significant difference in the use of anti-emetics (0.8 versus 0.6) (p = 0.60).  Hospital LOS averaged 2.2 days in the pain pump group and 2.5 days in the group without pain pumps (p = 0.09).  The authors concluded that the post-operative use of pain pumps in abdominoplasty patients did not significantly improve pain management.  Moreover, they stated that further investigation into this application of the pain pump is needed before recommending their routine use in abdominoplasty patients.

In a RCT, Sherwinter et al (2008) performed determined the safety and effectiveness of the On-Q pump delivery system for continuous infusion of intra-peritoneal bupivacaine after laparoscopic surgery. A total of 30 patients undergoing laparoscopic adjustable gastric banding were randomly assigned to one of two groups.  The treatment group received On-Q pump systems filled with 0.375 % bupivacaine, while the control group received pumps filled with 0.9 % normal saline.  The pump's catheter was introduced intra-peritoneally, and bupivacaine or saline was then delivered for the first 48 hours after surgery.  Patient's subjective pain scores were evaluated at preset intervals.  In addition, shoulder pain, morphine requirements, and anti-emetic requirements were tabulated.  A statistically significant decrease in patient's subjective reports of pain by VAS was noted in the On-Q group 1.8 +/- 1.93 versus control 3.5 +/- 2.4, p < 0.046 and remained significant until the end of the study (48 hours).  No statistical difference was noted in shoulder pain, morphine requirements, or anti-emetic requirements at any time-point.  The authors concluded that this study was able to provide evidence of significant reduction in post-operative pain as measured by subjective pain scores with the use of continuous intra-peritoneal bupivacaine using the On-Q pain pump system.  Moreover, they stated that further investigation is needed to evaluate the cost effectiveness of this technique.

Iyer et al (2010) noted that the continuous infusion of ropivacaine is effective in controlling pain for a wide variety of surgical procedures and reducing opioid adverse effects and dependency. The present study evaluated the effectiveness of ropivacaine infusion using the I-Flow dual Soaker catheter system at the surgical site for bariatric surgery recovery at the Dallas Veterans Affairs Medical Center Hospital (Dallas, TX).  These researchers hypothesized that patients receiving ropivacaine would report lower levels of morphine requirement and pain, would have shorter hospital stays, and would return to ambulating faster than patients in the control group.  A total of 45 patients undergoing Roux-en-Y gastric bypass surgery were randomized to 1 of 2 treatment groups, with a target study population of 50 patients, receiving either 0.2 % ropivacaine (n = 24) or saline solution (n = 21).  Before incision closure, the surgeon infiltrated the surrounding tissues with 30 ml of ropivacaine (0.5 %) or saline solution.  The catheter was then placed in both the sub-fascial space and subcutaneously.  Next, the infusion pump was connected to the Soaker Catheters to complete the system design and deliver solution to the surgical site.  No significant differences were found in the pain scores, morphine requirement, or LOS between the 2 groups.  The ropivacaine group interval to sitting up was 1/2 day shorter than that of patients receiving saline (p = 0.038).  The authors concluded that patients receiving ropivacaine were found to ambulate much more quickly than did the control group patients.  This could be very beneficial in reducing the complications from blood clots and improving patient recovery and overall well-being after surgery by assisting with a quicker return to activities of daily living and reducing the dependence on the nursing staff.

Cohen et al (2013) examined if continuous delivery of local anesthetic via an infusion pump system decreased post-operative opioid usage in post-RYGBP patients. The electronic health record was used to identify and review 289 patients who underwent RYGBP at the authors’ institution from January 2009 to October 2011.  The treatment group received a continuous infusion of 0.375 % bupivacaine administered by intra-peritoneal soaker catheter for 48 hours via an infusion pump; the control group did not receive a pump or local anesthetic.  Both groups received general anesthesia, nausea prophylaxis, and pain medication.  Pain management consisted of opioid-containing PCA for the 1st 24 hours.  Patients transitioned to supplemental intravenous opioid boluses, plus an oral opioid, for the remainder of their stay.  Opioid use was measured in terms of morphine equivalents; secondary outcomes included VAS pain scores and LOS.  Morphine equivalents over the post-operative time-point studied were significantly lower in the bupivacaine group than the control group (133 versus 106 mg, respectively; p = 0.001).  There was no significant difference in VAS scores between the 2 groups (p = 0.80).  Finally, the LOS between the 2 groups did not differ (p = 0.77).  The authors concluded that they have shown that continuous infusion of bupivacaine, administered via a pain pump system, may have decreased post-operative opioid utilization.  However, there were no differences in VAS scores or length of hospitalization between groups.

Medbery et al (2014) assessed the value of continuous wound infusion systems (CWIS) in patients following (LRYGBP. Records of all consecutive patients who underwent elective LRYGBP by a single surgeon from January 2008 until June 2010 were reviewed.  The presence of CWIS, patient pain scores, PACU times, post-operative narcotic and anti-emetic requirements, post-operative complications, and hospital LOS were recorded.  Clinical data were subsequently linked and correlated with hospital financial data to determine overall hospital costs.  A total of 44 LRYGBP patients were reviewed; 24 (54.5 %) received CWIS for post-operative pain control.  There was no significant difference in PACU times, post-operative LOS, or post-operative complications.  Patients with CWIS required significantly less narcotics (36.7 versus 55.5 mg IV morphine equivalents for total LOS; p = 0.03) and anti-emetics (5.0 versus 12.4 mg ondansetron for total LOS; p = 0.02); however, patients with CWIS did not report better pain control and had slightly higher hospital costs ($13,627.00 versus $13,395.05, p = 0.68).  The authors concluded that findings from the current study suggested that the value of CWIS for post-operative pain control following LRYGBP is limited.

Furthermore, an UpToDate review on "Bariatric surgery: Postoperative and long-term management of the uncomplicated patient" (Hamad, 2016) does not mention infusion pain pump as a management tool.

Anti-Emetic Infusion Pump

Second-line anti-emetics used in the treatment of nausea and vomiting during pregnancy include chlorpromazine, droperidol, metoclopramide, ondansetron, prochlorperazine, and promethazine (Smith et al, 2013).  However, the use of these anti-emetic agents by means of subcutaneous infusion pump is not established.

A review on "Nausea and vomiting in pregnancy" published in the Best Practice Journal (BPJ, 2011) noted that "Nausea and vomiting are very common symptoms of early pregnancy and usually resolve by 16 - 20 weeks gestation (most commonly by 12 weeks).  In most women these symptoms can be managed with simple diet and lifestyle advice and reassurance that it will not have an adverse effect on pregnancy.  Women with more severe symptoms may require pharmacological treatment and, in some cases, referral to hospital for intravenous fluids and antiemetics".  Administration of anti-emetics by means of subcutaneous pumps was not mentioned as a management option.

Reichmann and Kirkbride (2012) examined the medical evidence regarding the clinical efficacy and cost-effectiveness of the application of continuous subcutaneous metoclopramide and ondansetron to treat nausea and vomiting during pregnancy.  All of the published peer-reviewed articles on the subject were assembled and assigned a level of evidence based on research design.  The search uncovered 1 level II matched, controlled trial and 3 level III uncontrolled, retrospective case series published in peer-reviewed journals, as well as a book chapter.  The book chapter, although not subjected to the peer-reviewed process, is included in this review due to the paucity of other evidence.  The matched cohort trial showed that continuous subcutaneous metoclopramide is significantly less-tolerated than continuous subcutaneous ondansetron (31.8 % versus 4.4 %; p < 0.001).  The 4 case series reported complete symptom resolution for 63.9 % to 75 % of the patients.  Complications arose in 24.9 % to 30.5 % of the selected cases that were severe enough to require discontinuation of therapy.  Complications included side effects of a worsening of symptoms.  All of the trials were retrospective and observational in nature and, therefore, subject to the limitations inherent in the research design.  Absent the benefit of meaningful cohort controls, comparative statements effectiveness cannot be substantiated with the available data.  The authors concluded that randomized, controlled trials of sufficient power are necessary before long-term continuous subcutaneous metoclopramide or ondansetron can be used on a widespread basis to treat nausea and vomiting during pregnancy.  Cost approximations in the case series were reported and, when compared to the cost of other methods of treatment previously published in the medical literature, the therapy appears to be cost-prohibitive.  However, definitive statements cannot be made regarding cost-effectiveness until clinical efficacy is demonstrated through a sufficiently powered, well-designed RCT.  Until such time, the therapy should remain experimental; and coverage should be restricted to intractable hyperemesis gravidarum that is unresponsive to more-conventional treatment options.

An UpToDate review on "Treatment and outcome of nausea and vomiting of pregnancy" (Smith et al, 2013) states that "The use of subcutaneous pumps for timed release of medications, in particular metoclopramide, has been reported for outpatient management of nausea and vomiting in pregnancy with some benefit.  However, the experience is limited; we do not use them".

Ilfeld et al (2013) noted that there is currently no reliable treatment for phantom limb pain (PLP).  Chronic PLP and associated cortical abnormalities may be maintained from abnormal peripheral input, raising the possibility that a continuous peripheral nerve block (CPNB) of extended duration may permanently reorganize cortical pain mapping, thus providing lasting relief.  In a pilot study, 3 men with below-the-knee (n = 2) or below-the-elbow (n = 1) amputations and intractable PLP received femoral/sciatic or infra-clavicular perineural catheter(s), respectively.  Subjects were randomized in a double-masked fashion to receive perineural ropivacaine (0.5 %) or normal saline for over 6 days as outpatients using portable electronic infusion pumps.  Four months later, subjects returned for repeated perineural catheter insertion and received an ambulatory infusion with the alternate solution ("cross-over").  Subjects were followed for up to 1 year.  By chance, all 3 subjects received saline during their initial infusion and reported little change in their PLP.  One subject did not receive cross-over treatment, but the remaining 2 subjects reported complete resolution of their PLP during and immediately following treatment with ropivacaine.  One subject experienced no PLP recurrence through the 52-week follow-up period and the other reported mild PLP occurring once each week of just a small fraction of his original pain (pre-treatment: continuous PLP rated 10/10; post-treatment: no PLP at baseline with average of 1 PLP episode each week rated 2/10) for 12 weeks (lost to follow-up thereafter).  The authors concluded that a prolonged ambulatory CPNB may be a reliable treatment for intractable PLP.  They stated that the results of this pilot study suggested that a large, RCT is warranted.

Schwartzberg et al (2013) evaluated the effectiveness of continuous sub-acromial bupivacaine infusion to relieve pain after arthroscopic rotator cuff repair.  These researchers hypothesized that patients receiving continuous sub-acromial bupivacaine infusions after arthroscopic rotator cuff repair will have less post-operative pain in the early post-operative period than placebo and control groups.  A total of 88 patients undergoing arthroscopic rotator cuff repair were randomized in a blinded fashion into 1 of 3 groups.  Group 1 received no post-operative sub-acromial infusion catheter.  Group 2 received a post-operative sub-acromial infusion catheter filled with saline solution.  Group 3 received a post-operative sub-acromial infusion catheter filled with 0.5 % bupivacaine without epinephrine.  Infusion catheters were scheduled to infuse at 4 ml/hr for 50 hours.  Post-operative pain levels were assessed with VAS scores hourly for the first 6 post-operative hours, every 6 hours for the next 2 days, and then every 12 hours for the next 3 days.  Patients recorded daily oxycodone consumption for the first 5 post-operative days.  Immediately post-operative, the group with no catheter had significantly lower VAS scores (p = 0.04).  There were no significant differences in VAS scores among the groups at any other time-point.  There were no differences found among the groups regarding mean daily oxycodone consumption.  The authors concluded that the use of continuous bupivacaine sub-acromial infusion catheters resulted in no detectable pain reduction after arthroscopic rotator cuff repair based on VAS scores and narcotic medication consumption.

Herring et al (2014) stated that regional nerve blocks provide superior analgesia over opioid-based pain management regimens for traumatic injuries such as femur fractures.  An ultrasound-guided regional nerve block is placed either as a single-shot injection or via a perineural catheter that is left in place.  Although perineural catheters are commonplace in the peri-operative setting, their use by emergency physicians (EPs) for emergency pain management in adults has not been previously described.  Perineural catheters allow prolonged and titratable delivery of local anesthetic directly targeted to the injured extremity, resulting in opioid sparing while maintaining high-quality pain relief with improved alertness.  Despite these advantages, most EPs do not currently place perineural catheters, likely due to the widespread perception that the procedure is both excessively time consuming and too technically difficult to be practical in a busy emergency department (ED).  A catheter-over-needle kit, resembling a peripheral intravenous line, is now available and may be familiar to EPs than traditional catheter-needle assemblies.  Recent studies also suggested excellent analgesic outcomes with intermittent perineural bolusing of local anesthetic, thereby dispensing with the need for complex and expensive infusion pumps.  The authors described their successful placement of perineural femoral catheters at a busy inner-city public hospital ED.  They stated that their experience suggested that this is a promising new technique for emergency pain management of acute extremity injuries.

Continuous Subcutaneous Anti-Emetic Pump

Dickman and colleagues (2017) stated that a continuous subcutaneous infusion (CSCI) delivered via syringe pump is a method of drug administration used to maintain symptom control when a patient is no longer able to tolerate oral medication.  Several classes of drugs, such as anti-emetics, anti-cholinergics, anti-psychotics, benzodiazepines and opioids, are routinely administered by CSCI alone or in combinations.  Previous studies attempting to identify the most-common CSCI combinations are now several years old and no longer reflect current clinical practice.  These investigators reviewed current clinical practice and identified CSCI drug combinations requiring analysis for chemical compatibility and stability.  United Kingdom pharmacy professionals involved in the delivery of care to palliative patients in hospitals and hospices were invited to enter CSCI combinations comprised of 2 or more drugs onto an electronic database over a 12-month period.  In addition, a separate Delphi study with a panel of 15 expert healthcare professionals was completed to identify a maximum of 5 combinations of drugs used to treat more complex, but less commonly encountered symptoms unlikely to be identified by the national survey.  A total of 57 individuals representing 33 separate palliative care services entered 1,945 drug combinations suitable for analysis, with 278 discrete combinations identified.  The top 40 drug combinations represented nearly 2/3 of combinations recorded.  A total of 23 different drugs were administered in combination and the median number of drugs in a combination was 3.  The Delphi study identified 5 combinations for the relief of complex or refractory symptoms.  The authors concluded that this study represented the 1st step towards developing authoritative national guidance on the administration of drugs by CSCI.  They stated that further work will ensure healthcare practitioners have the knowledge and confidence that a prescribed combination will be both safe and effective.

Anesthetic Infusion Pump for Local Wound Infusion Following Laparoscopic Cholecystectomy

In a randomized, controlled, double-blind trial, Fassoulaki and colleagues (2016) examined the effect of ropivacaine infusion on pain after laparoscopic cholecystectomy.  A total of 110 patients were randomly assigned to 2 groups.  After induction of anesthesia a 75-mm catheter was inserted subcutaneously and connected to an elastomeric pump containing either 0.75 % ropivacaine (ropivacaine group) or normal saline (control group) for 24 hours post-operatively.  Before skin closure, each hole was infiltrated with 2 ml of 0.75 % ropivacaine or normal saline according to randomization.  Pain at rest, pain during cough, and analgesic consumption were recorded in the post-anesthesia care unit and at 2, 4, 8, 24, and 48 hours post-operatively.  Analgesic requirements and pain scores were recorded 1 and 3 months after surgery.  The ropivacaine group reported less pain during cough (p = 0.044) in the post-anesthesia care unit (p=0.017) and 4 hours post-operatively (p = 0.038). However, ropivacaine wound infusion had no effect on late and chronic pain.

Anesthetic Infusion Pump for Local Wound Infusion Following Cardiothoracic Surgery

In a retrospective, comparative analysis, Chopra and associates (2017) evaluated the effectiveness of local anesthesia, delivered via elastomeric pump to manage pain in patients undergoing cardiothoracic surgery.  Subjects were adult cardiothoracic surgery patients (by median sternotomy) who received continuous infusion bupivacaine + traditional methods for pain control (n = 100) or traditional pain control alone (n = 100) from July 2011 to October 2013.  The primary end-point was total post-operative opioid requirements for 96 hours following surgery; secondary end-points included post-operative pain scores, non-opioid analgesic requirements for 96 hours after surgery, and frequency of post-operative AEs.  Demographic characteristics were similar between both groups.  No difference was noted in overall opioid utilization for the 1st 96 hours post-operatively between the 2 groups (p = 0.36).  Similar pain scores were reported by patients in both groups for 96 hours following surgery, with the highest pain scores reported during the 1st 24 hours following surgery (p = 0.37).  No difference between groups was noted in utilization of ketorolac or acetaminophen; frequency of post-operative AEs, including the use of anti-emetic agents for nausea and vomiting, was similar in between both groups.  The authors concluded that the use of elastomeric pumps in patients undergoing cardiothoracic surgery for reducing post-operative opioid consumption and pain may not be as beneficial as previously reported.

Anesthetic Infusion Pump Following Unilateral Delayed Deep Inferior Epigastric Perforator Free Flap Reconstruction

Gatherwright and colleagues (2018) noted that effective post-surgical analgesia is a critical aspect of patient recovery.  In a prospective, randomized, controlled, blinded study, these researchers examined the effect that liposomal bupivacaine delivered via a transversus abdominis plane (TAP) block has on pain control in women undergoing unilateral deep inferior epigastic perforator reconstruction.  Patients were eligible if they were undergoing unilateral, delayed DIEP reconstruction.  Patients were randomized to 1 of 3 groups: liposomal bupivacaine or bupivacaine TAP block or bupivacaine pain pump.  Charts were reviewed for demographics, LOS, and post-operative narcotic utilization.  There were 8 patients in the liposomal bupivacaine and bupivacaine groups and 5 patients in the pain pump group.  A retrospective cohort of 6 patients who did not receive any intervention was included.  Patients who received a liposomal bupivacaine TAP block used statistically significantly less intravenous and total post-operative narcotics in mg and mg/kg/day compared to all other cohorts.  They were able to get out of bed earlier time point.  Overall hospital costs were similar amongst the groups.  The authors concluded that this was the first study to investigate liposomal bupivacaine delivered as a TAP block in a prospective, randomized, blinded study in women undergoing unilateral, delayed abdominally-based autologous breast reconstruction.  These investigators were able to demonstrate a significant reduction in intravenous and total narcotic utilization when a liposomal bupivacaine TAP block was utilized.  Moreover, they stated that future studies are needed to prospectively investigate the effect that liposomal bupivacaine would have on immediate and bilateral reconstructions.

Furthermore, UpToDate reviews on "Complications of reconstructive and aesthetic breast surgery" (Nahabedian and Gutowski, 2018) and "Overview of breast reconstruction" (Nahabedian, 2018) do not mention anesthetic infusion pump as a management tool.

Continuous Infusion of Local Anesthetic by Elastomeric Pump for Post-Operative Pain Management Following Donor Kidney Nephrectomy

Goldsby and colleagues (2022) stated that post-operative pain management following donor nephrectomy can prove challenging for immediate discharge on post-operative day 1 or 2.  Although the standard for pain control is utilization of opioids, this increases the risk of post-operative ileus and, if continued inappropriately, increases excess opioids circulating in the community.  One strategy that proposes to limit post-operative opioids in kidney donors is the continuous infusion of local anesthetics (CILA), although the effect on patient outcomes is unclear.  These researchers examined the effectiveness of post-operative CILA to decrease opioid usage in kidney donors who undergo laparoscopic nephrectomy.  They carried out a retrospective analysis of kidney donors who underwent laparoscopic nephrectomy and received CILA (CILA group) compared with kidney donors who received standard-of-care (SOC) post-operative analgesia.  The primary outcome was the mean total oral morphine equivalents (OMEs) administered following surgery.  A total of 176 kidney donors were evaluated, 88 in each group . The mean OME administered in the CILA group was significantly higher than in the SOC group: 194.8 versus 133.5 mg (p = 0.003).  Mean total post-operative administration of acetaminophen was also increased in the CILA group: 3,736.9 versus 2,611.6 mg (p = 0.0041).  Mean LOS following surgery was higher in the kidney donors who received CILA, whereas return to bowel function, time to ambulation, and pain scores were not significantly different.  The authors concluded that this study demonstrated that CILA was not an effective modality to reduce opioid utilization or improve recovery in kidney donors following laparoscopic nephrectomy.

Infusion Pump for Post-Operative Pain Management Following Arthroscopic Shoulder Surgery

An and colleagues (2020) noted that sub-acromial analgesia (SAA) is hypothesized to reduce pain following arthroscopic shoulder surgery by delivering a continuous infusion of local anesthetic directly to the surgical site.  In a systematic review and meta-analysis, these researchers examined the efficacy of SAA versus placebo for pain relief following arthroscopic sub-acromial shoulder procedures.  Medline, Embase, PubMed, and the Cochrane Central Register of Controlled Trials were searched for RCTs comparing SAA with placebo after arthroscopic shoulder surgery.  Outcomes collected included pain scores (converted to equivalent ordinal VAS; minimal clinically important difference 1.4 cm), OMEs used post-operatively, and catheter-related complications.  Meta-analysis was conducted via a random-effects model.  Included trials underwent a risk of bias and quality of evidence assessment.  A total of 9 studies involving 459 subjects were included.  There were no clinically significant changes for pain scores in SAA at 6-, 12-, 24-, and 48-hour post-operative time-points.  Patients receiving SAA used less OMEs of pain medication at 12 hours only (-0.37 mg, 95 % CI: -0.63 to -0.11); however, there was no significant difference at 24 and 48 hours.  There were no major complications (infection or re-operation).  Included trials demonstrated a moderate risk-of-bias, and low-to-very low quality of evidence for primary outcomes.  The authors concluded that sub-acromial continuous infusion of local anesthetic did not provide a clinically significant benefit compared with placebo as part of a multi-modal analgesia regimen following arthroscopic sub-acromial surgical procedures.  These researchers stated that future, high-quality trials are needed to further evaluate the efficacy of SAA against placebo.

Combined Dexmedetomidine and Morphine-Based Patient-Controlled Analgesia Pump for Management of Early Post-Operative Nausea in Women Undergoing Gynecological Laparoscopic Surgery

Li and colleagues (2020) stated that few studies have examined the effect of dexmedetomidine on PONV in patients underwent gynecological laparoscopic surgery.  In a prospective, randomized, double-blind and placebo-controlled study, these investigators examined if adding dexmedetomidine to a morphine-based PCA could decrease the incidence of PONV in this high-risk patient population.  In this trail, a total of 122 patients underwent gynecological laparoscopic surgery were assigned into 2 groups.  Patients in the dexmedetomidine group (Group Dex) received a loading dose of dexmedetomidine 0.4 μg/kg before the end of surgery, followed by morphine 0.5 mg/ml plus dexmedetomidine 1 μg/ml for post-operative i.v. PCA.  Patients in the control group (Group Ctrl) received normal saline before the end of surgery, followed by morphine 0.5 mg/ml alone for post-operative i.v. PCA.  PCA pump was programmed as followed: bolus dose 2-ml, lockout interval 8 mins, and background infusion at a rate of 1 ml/hour.  The primary outcome was the incidence of nausea and vomiting within the first post-operative 24 hours.  Although there were no significant differences regarding the total incidence of PONV (41.0 % versus 52.5 %, p = 0.204), PONV score, time to first onset of PONV, or the need for rescue antiemetics within the first post-operative 24 hours between the 2 groups, the incidence of nausea and total PONV during the first 2-hour period was significantly lower in the Group Dex than in the Group Ctrl (9.8 % versus 24.6 %, p = 0.031 and 0.031, respectively).  More patients in Group Dex were over-sedated or had bradycardia during the PACU compared with Group Ctrl (p = 0.040 and 0.036, respectively).  The authors concluded that their protocol in which dexmedetomidine was administered post-operatively -- after a loading dose -- to intravenous PCA morphine in patients undergoing gynecological laparoscopic surgery, had only early antiemetic effects, while no clinically meaningful antiemetic effect could be evidenced within the first 24 hours following surgery.

The authors stated that this study had several drawbacks.  First, PCA was programmed to deliver bolus with a background basal infusion of morphine with or without dexmedetomidine.  This continuous infusion dose of morphine might have masked the difference of opioid demands between groups.  Second, these researchers only chose 1 dose and the concentration of dexmedetomidine (1 μg/ml) was relatively small in PCA.  These investigators stated that further dose finding studies of dexmedetomidine are needed to confirm the safety and efficacy outcomes for these PONV susceptible patients.

Elastomeric Pump for Home Intravenous Administration of Antibiotics

Diamantis et al (2021) stated that over several decades, the economic situation and consideration of patient quality of life (QOL) have been responsible for increased outpatient treatment.  It is in this context that outpatient anti-microbial treatment (OPAT) has rapidly developed.  The availability of elastomeric infusion pumps has allowed prolonged or continuous antibiotic administration by means of a mechanical device necessitating neither gravity nor a source of electricity.  In many situations, its use optimizes administration of time-dependent antibiotics while freeing the patient from the constraints associated with infusion by gravity, volumetric pump or electrical syringe pump and, more often than not, limiting the number of nurse interventions to 1 or 2 per day.  These investigators noted that the installation of these pumps, which is not systematically justified, entails markedly increased OPAT costs and is liable to expose the patient to a risk of therapeutic failure or adverse effects due to the instability of the molecules used in a non-controlled environment, instability that necessitates close monitoring of their use.  More precisely, a prescriber must take into consideration the stability parameters of each molecule (infusion duration, concentration following dilution, nature of the diluent and pump temperature).  The authors examined the different means of utilization of elastomeric infusion pumps in intravenous antibiotic administration outside of hospital. 

The authors stated that the stability of antibiotics, which are often used in strong concentrations and exposed for lengthy periods of time to temperatures exceeding 25 degrees C, remains unknown.  Given the potentially heightened production of toxic metabolites and a lack of data on some molecules, it appeared necessary, with regard to each of them, to study the toxicity of the degradation products inside the devices.  As of now, OPAT in continuous or prolonged infusion by elastomeric pump is more and more widely used, necessitating enlightened prescription and surveillance.  Given the exceedingly low number of relevant and reliable data, these researchers’ proposals are based on a low level of evidence, which means that special attention should be paid to therapeutic effectiveness and the occurrence of adverse effects.  These researchers stated that further investigation is needed to establish more precise recommendations.

Karimaghaei et al (2022) noted that OPAT is an option for patients who require parenteral anti-microbials as outpatients.  Few OPAT studies have examined the impact of IV antibiotic therapy via elastomeric continuous pumps, with most having been performed outside the U.S. and few in county hospitals.  The OPAT program in Harris Health system, the county hospital system of Houston, Texas, has implemented a disposable elastomeric continuous infusion pump (eCIP) for self-administered intravenous antibiotics (s-OPAB) since December 2018.  In a retrospective study, these researchers described the clinical characteristics of patients discharged with an eCIP, as well as the safety and cost-effectiveness of this pump.  They analyzed patients discharged from Harris Health hospitals between December 2018 and February 2021 with s-OPAB via eCIP at home.  These investigators extracted various patient characteristics and outcomes related to OPAB.  Among 481 OPAB patients during the study period, 91 received s-OPAB via eCIP.  A total of 1,925 days of s-OPAB were administered at home, with a median duration of 12 days; 83 patients (93.4 %) achieved a cure from infection, 6 (6.6 %) had side effects, and 9 (9.9 %) experienced 30-day hospital re-admission; 22 patients (24.2 %) presented to the ED during s-OPAB, with 13 (14.3 %) presenting with peripherally inserted central catheter (PICC) line concerns.  These investigators estimated that s-OPAB via eCIP saved $2,360,500 to $3,503,900 compared to inpatient-only therapy.  The authors concluded that the findings of this study showed that patients with s-OPAB via eCIP had a high cure rate with a relatively low incidence of side effects and 30-day hospital re-admission; however, ED visits during therapy were relatively high, which indicated the necessity of close patient monitoring via the s-OPAB program.  Moreover, these researchers stated that further studies are needed to confirm these findings in other hospitals.

The authors stated that this study had several drawbacks.  As a retrospective study, the potential biases were inevitable.  Data collection relied on the availability of reported clinical information, and these researchers did not have access to the patient medical records outside their system, which potentially under-estimated the frequency of ED visits or other side effects.  Ideally, the study should compare this study group against a control group of patients with similar diagnoses and same antibiotics via only intermittent administration option; however, it was not feasible because these investigators were unable to match a sufficient number of patients by both diagnosis and anti-microbial therapy in the historical group.  Furthermore, if feasible, a prospective, randomized trial would provide a more definitive assessment of clinical outcome and cost savings among patients receiving home continuous IV antibiotic therapy via a disposable elastomeric pump.  Lastly, as this study was carried out only in county hospitals in Houston; thus, these findings may not be generalizable, follow-up studies are needed to confirm these findings.

Hepatic Arterial Infusion Pump Chemotherapy for Unresectable Intrahepatic Cholangiocarcinoma

Holster et al (2022) noted that patients with unresectable intrahepatic cholangiocarcinoma (iCCA) have poor survival.  In a systematic review and meta-analysis, these investigators examined the survival outcomes of hepatic arterial infusion pump (HAIP) chemotherapy with floxuridine for patients with unresectable iCCA.  They carried out a literature search using the electronic databases PubMed, Medline (Ovid), Embase, Web of Science, Google Scholar, and Cochrane to find studies that reported data on the survival of patients with unresectable iCCA treated with HAIP chemotherapy using floxuridine.  The quality of the studies was assessed using the Newcastle-Ottawa quality assessment Scale (NOS).  Overall survival (OS) was the primary outcome measure, and progression-free survival (PFS), response rates, resection rates, and toxicity were defined as secondary outcome measures.  After removing duplicates, 661 publications were assessed, of which 9 studies, representing a total of 478 patients, met the inclusion criteria; 3 out of 9 studies were phase-II clinical trials, 1 study was a prospective, dose-escalation trial, and the remaining 5 studies were retrospective cohort studies.  After accounting for overlapping cohorts, 154 unique patients were included for pooled analysis.  The weighted median OS of patients with unresectable iCCA treated with HAIP chemotherapy with floxuridine was 29.0 months (range of 25.0 to 39 months).  The pooled 1-, 2-, 3-, and 5-year OS were 86.4 %, 55.5 %, 39.5 %, and 9.7 %, respectively.  The authors concluded that HAIP chemotherapy with floxuridine for patients with unresectable iCCA was associated with a 3-year OS of 39.5 %, which was favorable compared with systemic chemotherapy for which no 3-year survivors were reported in the Advanced Biliary Cancer (ABC) trials.  Moreover, these researchers stated that even though these results were quite impressive, external validation of these findings is needed in addition to a RCT to optimally determine efficacy.

The authors stated that one of the main drawbacks of this systematic review was the lack of RCTs; however, 3 of the 9 studies were phase-II clinical trials with a pooled 3-year OS of 36.4 % compared with 0 % after systemic chemotherapy in the ABC trials.  Second, the number of studies and patients was small.  The small, pooled sample size resulted in less precision of the weighted and pooled OS estimates.  Even the lower limits of the 95 % CIs, however, markedly exceeded the 1-, 2-, and 3-year OS after systemic chemotherapy reported in the ABC trials.  Nevertheless, it should be noted that the 5-year OS is an imprecise estimate given the few patients who remain alive up to that point and the presence of large between-study heterogeneity.  Furthermore, patients were treated with different systemic chemotherapy regimens, which limited the homogeneity of the analyzed patients.  Another drawback was the heterogeneity of reported post-operative complications and toxicity that was partly due to the small sample sizes of the studies.  Finally, external validation is needed, because most studies originated from the same institution (i.e., Memorial Sloan Kettering Cancer Center [MSKCC]), making it difficult to translate HAIP chemotherapy as a more broadly applicable treatment modality.  Currently, a phase-II clinical trial examining OS after HAIP chemotherapy with floxuridine in patients with unresectable iCCA is ongoing in the Netherlands.  In addition, an ongoing international randomized clinical trial, initiated by MSKCC, is comparing systemic chemotherapy with or without HAIP with floxuridine for patients with unresectable iCCA.  Future trials on HAIP chemotherapy should also evaluate QOL measures.

NCCN guidelines on biliary tract cancers (2023) state that "Intra-arterial chemotherapy is recommended only in the context of a clinical trial or at experienced centers in carefully selected cases for patients with advanced disease confined to the liver."

Anesthetic Pain Pump for Post-Operative Management of Total Hip Arthroplasty

In a RCT, Keeka et al (2023)examined  if an addition of a local anesthetic pain pump for 48 hours post-operatively would affect LOS, opioid usage and verbal pain scores (VRS) following anterior approach total hip arthroplasty (THA).  This was a randomized, parallel-group, single-surgeon, single-center study with balanced randomization involving 108 patients.  Randomization and blinding were computer generated into 2 groups: local infiltration anesthetic (LIA) only (control group) and LIA+ continuous post-operative infusion of local anesthetic for 48 hours via a pain pump (intervention group).  Post-operatively VRS (first 30 mins, 1 hour, 2 hours and every 4 hours post-operatively up to 48 hours), opioid consumption, hospital LOS, anti-emetic and laxative usage were recorded.  Statistical analysis employed independent sample t-tests and repeated ANOVA.  Demographics and duration of surgery were similar across both cohorts.  On average, compared to the control group, the intervention group required 2 mg less of opioid consumption over 48 hours (p = 0.41).  VRS between the 2 groups showed no statistically significant difference.  Scores ranged from 0 to 7, with an average of 1.28 in the intervention group and 1.29 in the control group (p = 0.31); 9 patients in the intervention group and 10 in the control group required anti-emetics.  There was no difference in the LOS or post-operative constipation.  No complications or AEs occurred.  The authors concluded that this study demonstrated the addition of a continuous post-operative infusion of local anesthetic for 48 hours following an anterior THA had no effect on VRS, opioid consumption, LOS and anti-emetic usage.

Dual-Channel Elastomeric Pump for Intravenous Patient-Controlled Analgesia After Total Laparoscopic Hysterectomy

Oh et al (2022) stated that a newly designed intravenous PCA device with a dual-channel elastomeric infusion pump has been recently introduced.  One channel is a continuous line with a constant flow rate basal infusion, while the other channel has an adjustable flow rate and bolus function and is labeled as a selector-bolus channel.  These investigators compared dual and single-channel intravenous PCA in terms of clinical effect and quality of recovery.  A total of 84 patients undergoing total laparoscopic hysterectomy (TLH) were randomly allocated to a 1-channel group (n = 41) or a 2-channel group (n = 43).  Only the selector-bolus channel was utilized, but the continuous channel was not used in the 1-channel group, but both channels were employed in the 2-channel group.  In the 1-channel group, 16 μg/kg of fentanyl, 2 mg/kg of ketorolac, and 12 mg of ondansetron with normal saline were administered to the selector-bolus channel and normal saline only in the continuous channel for blinding.  In the 2-channel group, 16 μg/kg of fentanyl was administered to the selector-bolus channel, and ketorolac (2 mg/kg) and ondansetron (12 mg) were administered via the continuous channel.  The quality of recovery was evaluated pre-operatively and 24 hours post-operatively using the Quality of Recovery-40 (QoR-40).  Cumulative PCA consumption, post-operative pain rated using the numeric rating scale (NRS; during rest/cough), and post-operative nausea were evaluated 6, 12, 24, 36, and 48 hours following surgery.  Incidence of vomiting and use of anti-emetics and rescue analgesics was measured.  The 24-hour post-operative QoR-40 score was higher in the 2-channel group than in the 1-channel group (p = 0.031).  The incidence of nausea at 12 hours and 36 hours was significantly higher in the 1-channel group (p = 0.043 and 0.040, respectively), and anti-emetic use was more frequent in the 1-channel group (p = 0.049).  Patient satisfaction was higher in the 2-channel group (p = 0.036).  No significant differences were observed in pain scores during resting/cough or cumulative PCA consumption.  The authors concluded that the 2-channel PCA showed better patient satisfaction with higher QoR-40 during the recovery compared with the 1-channel PCA.  Better satisfaction was associated with lower nausea and reduced rescue antiemetics by maintaining the infusion of adjuvant analgesic agents and anti-emetic agents constantly by using dual channels.  These researchers stated that this trial examined the benefit of dual channel PCA over conventional single channel use; however, the clinical benefits of applying various modes of this device should be further studied.

The authors stated that this study had 2 main drawbacks.  First, even though the importance of avoiding different drugs mixture in the same pump was addressed, drugs were mixed in both groups (3 drugs in 1 channel group and 2 drugs in 2 channel group).  According to their in-vitro laboratory study, in the mixture of fentanyl, ketorolac, and ondansetron, safety issues, such as precipitation and incubation, did not happen, but the decrease in the concentration of ketorolac might happen at 24 and 48 hours.  This might affect their findings.  Second, the practices employed in this study were somewhat conventional and specified in the patients undergoing TLH in the Korean insurance and reimbursement system (relatively low charge); thus, it may be difficult to generalize their regimens.  However, it is thought that this did not affect the effect of dual-channel PCA itself.

References