Pulse Oximetry and Capnography for Home Use

Number: 0339

Table Of Contents

Policy
Applicable CPT / HCPCS / ICD-10 Codes
Background
References

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Policy

Scope of Policy

This Clinical Policy Bulletin addresses pulse oximetry and capnography for home use.

1. Medical Necessity

   Aetna considers pulse oximetry and capnography for home use medically necessary for following:

   1. Pulse oximeter for home use as durable medical equipment (DME) for members with chronic lung disease, severe cardiopulmonary disease or neuromuscular disease involving muscles of respiration, and any of the following indications:
      
      
      1. To determine appropriate home oxygen liter flow for ambulation, exercise, or sleep; or
      2. To monitor individuals on a ventilator at home; or
      3. Short-term (one month) monitoring when a change in the individual's physical condition requires a physician-directed adjustment in the liter flow of their home oxygen needs; or
      4. When weaning the individual from home oxygen; or
      5. For interstage monitoring of children undergoing the Norwood procedure for hypoplastic left heart syndrome.

      For information on the use of pulse oximetry in periodically re-assessing the need for long-term oxygen in the home, see CPB 0002 - Oxygen. Pulse oximetry can be used in conjunction with infant home apnea monitoring; for information on infant apnea monitors, see CPB 0003 - Apnea Monitors for Infants. Home pulse oximetry for indications other than those listed above may be considered medically necessary upon medical review.

   2. Capnography (end-tidal carbon dioxide (PETCO2) monitoring) for monitoring of members with congenital central alveolar hypoventilation syndrome. Note: Capnography is considered incidental to anesthesia or sedation services and is not separately reimbursed.

2. Experimental and Investigational

   1. Aetna considers the use of home pulse oximetry experimental and investigational for all other indications, including the following (not an all-inclusive list) because its effectiveness for these indications has not been established:
      
      
      1. Asthma management
      2. Diagnosing nocturnal hypoventilation associated with neuromuscular disorders
      3. Evaluating and teaching continuous positive airway pressure (CPAP)
      4. Evaluation of exertional desaturation in individuals with COVID-19
      5. Maintenance or continuous monitoring (other than for persons on a ventilator)
      6. Predicting the need of adenotonsillectomy in children
      7. When used alone as a screening/testing technique for suspected obstructive sleep apnea.
   2. Aetna considers capnography experimental and investigational for all other indications, including the following (not an all-inclusive list) because its effectiveness for these indications has not been established:
      
      
      1. Pre-screening of sleep-disordered breathing after stroke
      2. Assessment of prognosis following cardiac arrest.

3. Related Policies

   • CPB 0004 - Obstructive Sleep Apnea in Adults 
   • CPB 0479 - Respiratory Devices: Incentive Spirometers, Vaporizers and Intermittent Positive Pressure Breathing Machines
   • CPB 0572 - Home/Ambulatory Spirometry

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Table:

CPT Codes / HCPCS Codes / ICD-10 Codes

Code	Code Description
Information in the [brackets] below has been added for clarification purposes.   Codes requiring a 7th character are represented by "+":
Pulse Oximetry:
CPT codes covered if selection criteria is met:
94760	Noninvasive ear or pulse oximetry for oxygen saturation; single determination
94761	multiple determinations (e.g., during exercise)
94762	by continuous overnight monitoring (separate procedure)
Other CPT codes related to the CPB:
42820	Tonsillectomy and adenoidectomy; younger than age 12
42821	age 12 or over
94660	Continuous positive airway pressure ventilation (CPAP), initiation and managemenmt [Pulse oximetry is not covered when performed in home for evaluating and teaching on CPAP use]
HCPCS codes covered if selection criteria are met:
A4606	Oxygen probe for use with oximeter device, replacement
E0445	Oximeter device for measuring blood oxygen levels non-invasively
Other HCPCS codes related to the CPB:
E0424 - E0444, E0455 - E0484	Oxygen and related respiratory equipment
ICD-10 codes covered if selection criteria are met (not all-inclusive):
D75.1	Secondary polycythemia
E84.0 - E84.9	Cystic fibrosis
G70.9	Myoneural disorder, unspecified [neuromuscular disease]
I20.1 - I20.9	Angina pectoris
I27.0 - I27.9	Other pulmonary heart diseases
I50.20 - I50.9	Congestive heart failure
I73.9	Peripheral vascular disease, unspecified
J43.0 - J43.9	Emphysema
J44.9	Chronic obstructive pulmonary disease, unspecified
J47.0 - J47.9	Bronchiectasis
J80	Acute respiratory distress syndrome
J84.10	Pulmonary fibrosis, unspecified
J95.1 - J95.3, J95.821 - J95.822	Pulmonary insufficiency following trauma and surgery
J96.00 - J96.92	Respiratory failure [neuromuscular disease]
J98.4	Other disorders of lung [neuromuscular disease]
J98.6	Disorders of diaphragm [neuromuscular disease]
P22.0	Respiratory distress syndrome of newborn
P22.1 - P28.9	Other respiratory conditions of fetus and newborn
Q23.4	Hypoplastic left heart syndrome [for interstage monitoring of children undergoing the Norwood procedure]
R06.81	Apnea, not elsewhere classified
R09.02	Hypoxemia
Z99.11	Dependence on respirator [ventilator] status
Z99.81	Dependence on supplemental oxygen
ICD-10 codes not covered for indications listed in the CPB (not all inclusive):
F51.8	Other sleep disorders not due to a substance or known physiological condition
G47.00 - G47.20 G47.30 - G47.39 G47.61 - G47.69 G47.8 - G47.9	Sleep disorders
J12.82	Pneumonia due to coronavirus disease 2019
J45.20 - J45.998	Asthma
U07.1	COVID-19
Z13.83	Encounter for screening for respiratory disorder, not elsewhere classified
Capnography (PETCO2 monitoring) :
ICD-10 codes covered if selection criteria are met (not all-inclusive):
G47.35	Congenital central alveolar hypoventilation syndrome
ICD-10 codes not covered for indications listed in the CPB (not all inclusive):
I46.2 - I46.9	Cardiac arrest
I63.00 - I63.9	Cerebral infarction [pre-screening of sleep-disordered breathing after stroke]
Z13.83	Encounter for screening for respiratory disorder, not elsewhere classified

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Background

Oximeters are noninvasive monitors that measure the oxygen saturation of blood. They are often also referred to as "pulse oximeters" because they also measure and record an individual’s heart rate. A sensor is placed on a finger, toe or ear and uses light to estimate the oxygen saturation in the arterial blood; the sensor is connected by a wire to a monitor, which then displays both the oxygen saturation (O2 sat) and the heart rate.

Home oximetry may be used to monitor the O2 sat in the blood of individuals with known or suspected heart disease or many other circulatory or lung disorders. It may be considered medically necessary to assist the physician in determining the correct flow of supplemental oxygen, monitor changes in O2 sat during exercise and assist with management of home ventilators. The units used in the home are usually small, portable hand-held devices, though they can be larger, stationary machines.

For patients on long-term oxygen therapy, pulse oximetry arterial oxygen saturation (SaO2) measurements are unnecessary except to assess changes in clinical status, or to facilitate changes in the oxygen prescription.  Home pulse oximetry is also indicated when there is a need to monitor the adequacy of SaO2 or the need to quantitate the response of SaO2 to a therapeutic intervention.

A National Heart, Lung and Blood Institute/World Health Organization Global Asthma Initiative Report concluded that pulse oximetry was not an appropriate method of monitoring patients with asthma.  The report explained that, during asthma exacerbations, the degree of hypoxemia may not accurately reflect the underlying degree of ventilation-perfusion (V-Q) mismatch.  Pulse oximetry alone is not an efficient method of screening or diagnosing patients with suspected obstructive sleep apnea (OSA).  The sensitivity and negative predictive value of pulse oximetry is not adequate to rule out OSA in patients with mild to moderate symptoms.  Therefore, a follow-up sleep study would be required to confirm or exclude the diagnosis of OSA, regardless of the results of pulse oximetry screening.

Home overnight pulse oximetry (OPO) has been used to evaluate nocturnal desaturation in patients with chronic obstructive pulmonary diseases (COPD).  However, Lewis et al (2003) found that nocturnal desaturation in patients with COPD exhibited marked night-to-night variability when measured by home OPO.  A single home OPO recording may be insufficient for accurate assessment of nocturnal desaturation.  Gay (2004) stated that for COPD patients who exhibit more profound daytime hypercapnia, polysomnography is preferred over nocturnal pulse oximetry to rule out other co-existing sleep-related breathing disorders such as OSA (overlap syndrome) and obesity hypoventilation syndrome.

In a retrospective case-series study, Bauman et al (2013) determined the utility of home-based, unsupervised transcutaneous partial pressure of carbon dioxide (tc-Pco(2)) monitoring/oxygen saturation by pulse oximetry (Spo(2)) for detecting nocturnal hypoventilation (NH) in individuals with neuromuscular disorders.  Subjects (n = 35, 68.6 % men; mean age of 46.9 yrs) with spinal cord injury (45.7 %) or other neuromuscular disorders underwent overnight tests with tc-Pco(2)/Spo(2) monitoring.  Fifteen (42.9 %) were using nocturnal ventilatory support, either bilevel positive airway pressure (BiPAP) or tracheostomy ventilation (TV).  A respiratory therapist brought a calibrated tc-Pco(2)/Spo(2) monitor to the patient's home and provided instructions for data collection during the subject's normal sleep period.  Forced vital capacity (FVC), body mass index (BMI), and exhaled end-tidal Pco(2) (ET-Pco(2)) were recorded at a clinic visit before monitoring.  Main outcome measure was detection of NH (tc-Pco(2) greater than or equal to 50 mmHg for greater than or equal to 5 % of monitoring time).  Data were also analyzed to determine whether nocturnal oxygen desaturation (Spo(2) less than or equal to 88 % for greater than or equal to 5 % of monitoring time), FVC, BMI, or daytime ET-Pco(2) could predict the presence of NH.  Nocturnal hypoventilation was detected in 18 subjects (51.4 %), including 53.3 % of those using BiPAP or TV.  Nocturnal hypoventilation was detected in 43.8 % of ventilator-independent subjects with normal daytime ET-Pco(2) (present for 49.4 % +/- 31.5 % [mean +/- SD] of the study period), and in 75 % of subjects with an elevated daytime ET-Pco(2) (present for 92.3 % +/- 8.7 % of the study period).  Oxygen desaturation, BMI, and FVC were poor predictors of NH.  Only 3 attempted monitoring studies failed to produce acceptable results.  The authors concluded that home-based, unsupervised monitoring with tc-Pco(2)/Spo(2) is a useful method for diagnosing NH in neuromuscular respiratory failure (NMRF).  The findings of this small retrospective case-series study need to be validated by well-designed studies.

Nardi et al (2012) noted that pulse oximetry alone has been suggested to determine which patients on home mechanical ventilation (MV) require further investigation of nocturnal gas exchange.  In patients with neuromuscular diseases, alveolar hypoventilation (AH) is rarely accompanied with ventilation-perfusion ratio heterogeneity, and, therefore, oximetry may be less sensitive for detecting AH than in patients with lung disease.  These investigators examined if Spo(2) and tc-Pco(2) during the same night were interchangeable or complementary for assessing home MV efficiency in patients with neuromuscular diseases.  Data were collected retrospectively from the charts of 58 patients with chronic NMRF receiving follow-up at a home MV unit.  Spo(2) and tc-Pco(2) were recorded during a 1-night hospital stay as part of standard patient care.  These researchers compared AH detection rates by tc-Pco(2), Spo(2), and both.  Alveolar hypoventilation was detected based on tc-Pco(2) alone in 24 (41 %) patients, and based on Spo(2) alone with 3 different cut-offs in 3 (5 %), 8 (14 %), and 13 (22 %) patients, respectively.  Using both tc-Pco(2) and Spo(2) showed AH in 25 (43 %) patients.  The authors concluded that pulse oximetry alone is not sufficient to exclude AH when assessing home MV efficiency in patients with neuromuscular diseases.  Both tc-Pco(2) and Spo(2) should be recorded overnight as the first-line investigation in this population.

Also, UpToDate reviews on "Respiratory muscle weakness due to neuromuscular disease: Clinical manifestations and evaluation" (Epstein, 2013a); "Respiratory muscle weakness due to neuromuscular disease: Management" (Epstein, 2013b); "Continuous noninvasive ventilatory support for patients with neuromuscular or chest wall disease" (Bach, 2013), and "Types of noninvasive nocturnal ventilatory support in neuromuscular and chest wall disease" (Hill and Kramer, 2013) do not mention the use of home pulse oximetry.

Studies have demonstrated improvements in survival of infants undergoing the Norwood procedure for hypoplastic left heart syndrome with interstage monitoring with home pulse oximetry (Ghanayem et al, 2003; Dobrolet et al, 2011; Hansen et al, 2012).

In a feasibility study, Cross et al (2012) noted that strategies to reduce inter-stage morbidity and mortality for patients with single ventricle following stage I palliation included standardized care protocols, focused high-risk outpatient clinics, dedicated teams that focus on the unique needs of these fragile patients and use of home surveillance monitoring.  Use of telemedicine devices for home monitoring has been shown to improve outcomes in adults.  These devices allow for a more automated approach to home monitoring that have many advantages.  These researchers described their program that utilizes a web-based telemedicine device to capture and transmit data from the homes of their patients during the inter-stage period.  The authors stated that their early data suggested that home telemedicine is feasible, provides a more systematic data review and analysis and supports the assertion that patients using home surveillance have significantly better nutritional status than those not using home monitoring.

Ohman et al (2013) stated that shunt occlusion is a major cause of death in children with single ventricle.  These investigators evaluated whether one daily measurement of oxygen saturation at home could detect life-threatening shunt dysfunction.  A total of 28 infants were included in this study.  Parents were instructed to measure saturation once-daily and if less than or equal to 70 % repeat the measurement.  Home monitoring was defined as positive when a patient was admitted to Queen Silvia Children's Hospital because of saturation less than or equal to 70 % on repeated measurement at home.  A shunt complication was defined as arterial desaturation and a narrowing of the shunt that resulted in an intervention to relieve the obstruction or in death.  Parents' attitude towards the method was investigated using a questionnaire.  A shunt complication occurred out of hospital 8 times in 8 patients.  Home monitoring was positive in 5 out of 8 patients.  In 2 patients, home monitoring was probably life-saving; in 1 of them, the shunt was replaced the same day and the other had an emergency balloon dilatation of the shunt.  In 3 out of 8 patients, home monitoring was negative; 1 had an earlier stage II and survived, but 2 died suddenly at home from thrombotic shunt occlusion.  On 7 occasions in 3 patients, home monitoring was positive but there was no shunt complication.  The method was well accepted by the parents according to the results of the questionnaire.  The authors concluded that home monitoring of oxygen saturation has the potential to detect some of the life-threatening shunt obstructions between stages I and II in infants with single-ventricle physiology.

Also, an UpToDate review on "Management and outcome of heterotaxy (isomerism of the atrial appendages)" (Lowental et al, 2014) states that "Single ventricle physiology is predominant in RAI [right atrial isomerism], as patients usually have a hypoplastic left ventricle.  These patients also typically have asplenia, as the spleen is a left-side abdominal organ.  In general, patients with RAI most often present during the neonatal period with cyanosis due to right-to-left shunting as a result of pulmonary outflow obstruction and septal defects between the atria and ventricles.  In severely affected neonates, survival is dependent on maintaining a patent ductus arteriosus.  In other cases, respiratory distress may develop because of pulmonary congestion due to pulmonary venous obstruction …. Single ventricle palliation – Similar to other univentricular conditions, palliative management beginning in the neonate generally consists of a series of staged procedures, which vary with the underlying lesions …. Initial neonatal shunting – Follow-up visits are frequent for neonates who undergo palliative shunting to secure either pulmonary blood flow or systemic blood flow.  At each visit, the clinical status is evaluated with a focus on the adequacy of oxygen saturation and somatic growth.  As many of these single ventricle patients have ventricular overload and abnormal atrioventricular valves, surveillance echocardiograms are performed on a monthly basis to monitor for the development of atrioventricular insufficiency".  Moreover, this review does not mention the use of home pulse oximetry as a management tool.

In a Cochrane review, Welsh et al (2015) examined if pulse oximeters used as part of a personalized asthma action plan for people with asthma are safer and more effective than a personalized asthma action plan alone.  These investigators searched the Cochrane Airways Group Specialised Register (CAGR), which includes reports identified through systematic searches of bibliographic databases including the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), the Allied and Complementary Medicine Database (AMED) and PsycINFO, and by hand-searching.  They also searched ClinicalTrials.gov and the World Health Organization (WHO) trials portal.  These researchers planned to include randomized controlled trials (RCTs).  Participants would have included adults, children or both with a diagnosis of asthma.  They planned to include trials in which investigators compared participants who used pulse oximeters to monitor oxygen levels at home during an asthma exacerbation as part of a personalized asthma action plan (PAAP) versus those who used a PAAP without a pulse oximeter.  They planned to include studies involving people receiving any treatment regimen provided that no medicine was included as part of the randomization schedule.  The authors planned to use standard methods as recommended by The Cochrane Collaboration.  They found no studies and no evidence to support or refute the use of home pulse oximetry in self-management of asthma; thus, they could not make any recommendations about use of a pulse oximeter as part of a PAAP.  The authors concluded that they found no reliable data to support or refute patient use of pulse oximeters to monitor oxygen saturation levels when experiencing an asthma attack.  They stated that individuals should not use a pulse oximeter without seeking advice from a qualified healthcare professional.  They identified no compelling rationale for home monitoring of oxygen levels in isolation for most people with asthma.  Some people have a reduced perception of the severity of their own breathlessness when exposed to hypoxia.  If trials on self-monitoring of oxygen levels in the blood by pulse oximeter at home by people with asthma are conducted, the pulse oximeter must be given as part of a personalized asthma action plan.

Predicting the Need of Adenotonsillectomy in Children

Pavone and colleagues (20170 stated that nocturnal pulse oximetry has a high positive predictive value for polysomnographically diagnosed OSA in children.  When significant adenotonsillar hypertrophy is diagnosed, adenotonsillectomy (T&A) represents a common treatment for OSA in children.  These investigators examined the role of pulse oximetry in predicting those patients, referred for suspected OSA, who subsequently needed T&A.  At-home nocturnal pulse oximetry was performed on 380 children (65.7 % males), median age of 4.1 (IRQ 3.0 to 5.6) years, referred for suspected OSA, and data were retrospectively analyzed.  For each recording McGill Oximetry Score (MOS) was categorized.  Mean pulse rate (PR) z-score and pulse rate variability (PRV)-corrected (PRSD/mean PR) were significantly higher in children with abnormal MOS.  Both parameters were significantly higher in subjects who underwent T&A compared with those not surgically treated.  Both DI4 and PRV corrected showed a negative correlation with the elapsed time between pulse oximetry recordings and T&A.  The logistic regression model showed a strong effect of an abnormal MOS as a predicting factor for T&A (adjusted odds ratio [OR] of 19.7).  The authors concluded that children with OSA who subsequently needed T&A showed higher PRV compared to those without surgical indication.  Children with abnormal MOS were nearly 20 times more likely to undergo T&A.  They stated that nocturnal pulse oximetry had a high positive predictive value for polysomnographically diagnosed OSA in children.  When significant adenotonsillar hypertrophy is diagnosed, adenotonsillectomy represents a common treatment for OSA in children.  Moreover, they noted that an abnormal pulse oximetry highly predicted the indication for adenotonsillectomy.  They suggested that the use of at-home pulse oximetry as a method to predict prescription of adenotonsillectomy, and this may be useful in contexts where polysomnography is not readily available.

Congenital Central Hypoventilation Syndrome

The American Thoracic Society’s clinical policy statement on "Congenital central hypoventilation syndrome" (Weese-Mayer and colleagues, 2010) stated that congenital central hypoventilation syndrome (CCHS) is characterized by alveolar hypoventilation and autonomic dysregulation.  It noted that pulse oximeter and end tidal carbon dioxide (CO2) monitors are usually set to alarm for peripheral capillary oxygen saturation (SpO2) of 85 % or less and end-tidal carbon dioxide (PETCO2) of 55 mm Hg or greater, respectively.  Moreover, the guideline noted that some centers use ‘‘ventilator ladders’’ in conjunction with pulse oximetry and PETCO2 monitoring to maintain precise control of gas exchange within a narrow normal range.  It is important to maintain normal oxygenation to avoid risk for deficits in cognition.

Furthermore, an UpToDate review on "Congenital central hypoventilation syndrome and other causes of sleep-related hypoventilation in children" (Brouillette, 2018) states that "Continuous pulse oximetry should be used for in-hospital and at-home monitoring of CCHS patients.  At all times, a caretaker capable of evaluating and responding to such life-threatening events as ventilator disconnection, tracheostomy decannulation, or blockage must be immediately available in case of alarm.  Adequacy of ventilation should be assessed intermittently with a PETCO2 monitor, particularly if supplemental oxygen is being used; supplemental oxygen may obscure clinically significant hypoventilation.  Downloads of data from the oximeter can provide assurance of adequate ventilatory support over longer periods".

Home Pulse Oximetry for Exertional Desaturation in COVID-19

Kalin and colleagues (2021) stated that even when resting pulse oximetry is normal in the patient with acute coronavirus disease-2019 (COVID-19), hypoxia can manifest on exertion.  These researchers examined the available evidence on the performance of different rapid tests for exertional desaturation (i.e., a fall of 3 % or more in pulse oximetry reading on exercise) and drew on this evidence base to provide guidance in the context of acute COVI-19.  These investigators addressed the following 2 questions: First: What exercise tests have been used to evaluate exertional hypoxia at home or in an ambulatory setting in the context of COVID-19 and to what extent have they been validated?  Second: What exercise tests have been used to evaluate exertional hypoxia in other lung conditions, to what extent have they been validated and what is the applicability of these studies to acute COVID-19?  AMED, CINAHL, Embase, Medline, Cochrane and PubMed using LitCovid, Scholar and Google databases were searched to September 2020.  Studies where participants had COVID-19 or another lung disease and underwent any form of exercise test that was compared to a reference standard were eligible.  Risk of bias was assessed using QUADAS 2.  A protocol for the review was published on the Medrxiv database.  Of 47 relevant papers, 15 were empirical studies, of which 11 described an attempt to validate 1 or more exercise desaturation tests in lung diseases other than COVID-19.  In all but 1 of these, methodological quality was poor or impossible to fully assess.  None had been designed as a formal validation study (most used simple tests of correlation).  Only 1 validation study (comparing a 1-min sit-to-stand test [1MSTST] with reference to the 6-min walk test [6MWT] in 107 patients with interstitial lung disease [ILD]) contained sufficient raw data for these researchers to calculate the sensitivity (88 %), specificity (81 %) and positive and negative predictive value (PPV and NPV of 79 % and 89 %, respectively) of the 1MSTST.  The other 4 empirical studies included 2 predictive studies on patients with COVID-19, and 2 on HIV-positive patients with suspected pneumocystis pneumonia.  These investigators found no studies on the 40-step walk test (a less demanding test that is widely used in clinical practice to evaluate COVID-19 patients).  Heterogeneity of study design precluded meta-analysis.  The authors concluded that exertional desaturation tests have not yet been validated in patients with (or suspected of having) COVID-19.  A stronger evidence base exists for the diagnostic accuracy of the 1MSTST in chronic long-term pulmonary disease; the relative intensity of this test may raise safety concerns in remote consultations or unstable patients.  The less strenuous 40-step walk test should be urgently evaluated.  These investigators stated that more research is needed on the prognostic value and clinical use of exertional desaturation tests in all settings in the context of COVID-19.  Furthermore, an understanding of how best to ask the patient regarding breathlessness on exertion, and how this correlates with exertion oximetry, could also help in the evaluation of hypoxia in COVID-19.

Alboksmaty et al (2022) noted that the COVID-19 pandemic has led health systems to increase the use of tools for monitoring and triaging patients remotely.  In a systematic review, these investigators examined the safety and effectiveness of pulse oximetry in remote patient monitoring (RPM) of patients at home with COVID-19.  They searched 5 databases (Medline, Embase, Global Health, medRxiv, and bioRxiv) from database inception to April 15, 2021, and included feasibility studies, clinical trials, and observational studies, including preprints.  These researchers found 561 studies, of which 13 were included in this narrative synthesis.  These 13 studies were all observational cohorts and involved a total of 2,908 subjects.  A meta-analysis was not feasible owing to the heterogeneity of the outcomes reported in the included studies.  This systematic review substantiated the safety and potential of pulse oximetry for monitoring patients at home with COVID-19, identifying the risk of deterioration and the need for advanced care.  The authors stated that the use of pulse oximetry could potentially save hospital resources for patients who might benefit the most from care escalation; however, these investigators could not identify explicit evidence for the effect of RPM with pulse oximetry on health outcomes compared with other monitoring models such as virtual wards, regular monitoring consultations, as well as online or paper diaries to monitor changes in symptoms and vital signs.  The authors concluded that the COVID-19 pandemic has placed RPM as a leading interest in public health research.  Given the current knowledge regarding COVID-19, pulse oximetry is potentially an effective tool for monitoring deterioration and keeping patients safe at home.  The model was deemed safe for application and use in some different contexts among different populations.  Research into the cost-effectiveness of RPM with pulse oximetry is scarce at present, and available data regarding its effect on the use of healthcare services are inconclusive.  These investigators stated that further research is needed to inform the future implementation of pulse oximetry in monitoring patients with COVID-19.  This research should entail more diverse populations, test the system in resource-limited settings, and examine the effect on health outcomes compared with other systems.

Capnography for Use during Gastro-Intestinal Endoscopic Sedation

Kim and colleagues (2018) stated that the use of capnography monitoring devices has been shown to lower the rates of hypoxemia via early detection of respiratory depression, and facilitate more accurate titration of sedatives during procedures.  In a meta-analysis, these investigators compared the incidence of hypoxemia associated with standard monitoring alone during gastro-intestinal (GI) endoscopy to that associated with standard monitoring with the addition of capnography.  The Medline, Embase, and Cochrane Central Register of Controlled Trials scientific databases were searched to identify relevant studies.  They performed a meta-analysis of RCTs undertaken up to January 2018 that met pre-defined inclusion criteria.  The study outcome measures were incidence of hypoxemia, severe hypoxemia, apnea, the use of assisted ventilation, the use of supplemental oxygen, and change in vital signs.  These researchers included 9 trials assessing a total of 3,088 patients who underwent GI procedural sedation.  Meta-analysis of study outcome revealed that capnography significantly reduced the incidence of hypoxemia (OR 0.61, 95 % confidence interval [CI]: 0.49 to 0.77) and severe hypoxemia (OR 0.53, 95 % CI: 0.35 to 0.81).  However, there were no significant differences in other outcomes including incidence of apnea, assisted ventilation, supplemental oxygen, and changes in vital signs.  Early procedure termination and patient satisfaction-related outcomes did not differ significantly in the capnography group and the standard monitoring group.  The authors concluded that the findings of this study indicated that capnography monitoring was associated with reduced incidence of hypoxemia during GI procedural sedation, and there was no evidence of an association with procedural interruption.  They stated that capnography monitoring should be considered in routine monitoring in the near future.  These researchers stated that further studies with larger numbers of patients are needed to clarify the beneficial effects of capnography during GI endoscopic sedation.

The authors stated that this study had several drawbacks that should be taken into account when interpreting the results.  First, it included studies that varied with respect to the sedative agents and corresponding doses used.  This may account for some of the heterogeneity in the results of the analysis.  Second, because the analysis was based on only 8 RCTs, these investigators did not perform sub-group analysis based on the type of endoscopic procedure.  Thus, it could not be decisively concluded that diagnostic and therapeutic endoscopy had similar safety with regard to sedation.  These researchers also analyzed both upper endoscopy through the oral cavity and colonoscopy together. 

Capnography for Prognosis Following Cardiac Arrest

In a systematic review, Paiva and co-workers (2018) examined if any level of ETCO2 measured during cardio-pulmonary resuscitation (CPR) correlates with return of spontaneous circulation (ROSC) or survival in adults experiencing cardiac arrest in any setting.  These researchers included RCTs, cohort studies, and case-control studies of adult cardiac arrest in any setting that reported specific (rather than pooled) ETCO2 values and attempted to correlate those values with prognosis.  Full-text articles were searched on Embase, Medline, and Cochrane Database.  The Grades of Recommendation, Assessment, Development and Evaluation (GRADE) guidelines were followed, assigning levels of quality to all evidence used in the meta-analysis.  A total of 17 observational studies, describing 6,198 patients, were included in the qualitative synthesis, and 5 studies were included in the meta-analysis.  The available studies provided consistent but low-quality evidence that ETCO2 measurements of greater than or equal to 10 mmHg, obtained at various time-points during CPR, were substantially related to ROSC; additional cut-off values were also found.  Initial ETCO2 or 20-min ETCO2 of greater than 20 mmHg appeared to be a better predictor of ROSC than the 10 mmHg cut-off value.  A ETCO2 of less than 10 mmHg after 20 mins of CPR was associated with a 0.5 % likelihood of ROSC.  The authors concluded that based upon existing evidence, ETCO2 levels appeared to provide limited prognostic information for patients who had experienced cardiac arrest.  Moreover, these researchers stated that given the many potential confounders that could influence initial ETCO2 levels, extreme or trending values may be more useful than static mid-range levels.  They stated that additional well-designed studies are needed to define optimal timing for the measurement of ETCO2 for prognostic purposes.

Capnography for Pre-Screening of Sleep-Disordered Breathing after Stroke

Takala and colleagues (2018) noted that sleep-disordered breathing (SDB) is frequent in stroke patients.  Polysomnography (PSG) and cardio-respiratory polygraphy are used to confirm SDB, but the need for PSG exceeds the available resources for systematic testing.  Thus, a simple and robust pre-screening instrument is necessary to identify the patients with an urgent need for a targeted PSG.  In a systematic review, these investigators evaluated the available methods to pre-screen stroke patients possibly suffering from SDB.  A total of 11 studies out of 3,561 studies met the inclusion criteria.  The selected studies assessed the efficiency of 7 instruments based on the data acquired clinically or by inquiries (Berlin Questionnaire, Epworth Sleepiness Scale, SOS, Modified Sleep Apnea Scale of the Sleep Disorders Questionnaire, STOP-BANG, Four-variable Screening Tool and Multivariate Apnea Index) and 3 physiological measures (capnography, nocturia, nocturnal oximetry).  The instruments were used to predict SDB in patients after acute or sub-acute stroke.  Either PSG or cardio-respiratory polygraphy was used as a standard to measure SDB.  No independent studies using the same questionnaires, methods or criteria were published reducing generalizability.  Overall, the questionnaires were quite sensitive in finding SDB but not highly specific in identifying the non-affected.  The physiological measures (capnography) indicated promising results in predicting SDB, but capnography is not an ideal pre-screening instrument as it requires a specialist to interpret the results.  The authors concluded that the findings of pre-screening of SDB in acute and sub-acute stroke patients are promising but inconsistent.  The current pre-screening methods could not readily be referred to clinicians in neurologic departments.  Thus, it is necessary to conduct more research on developing novel pre-screening methods for detecting SDB after stroke.

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References