Routine Postoperative Monitoring after Bariatric Surgery in Morbidly Obese Patients with Severe Obstructive Sleep Apnea: ICU Admission is not Necessary

Maxillomandibular Advancement Safety and Effectiveness in Obstructive Sleep Apnea: Systematic Review and Meta-Analysis

OBJECTIVE

To provide an updated evaluation of clinical effectiveness and sequelae of maxillomandibular advancement surgery in obstructive sleep apnea.

DATA SOURCES

PubMed, Scopus, CINAHL.

REVIEW METHODS

Included studies described patients with obstructive sleep apnea that completed maxillomandibular advancement with any reported sequelae. Meta-analysis of proportions, regressions, and single means with 95% confidence interval were calculated using random and fixed effects models.

RESULTS

Of 380 unique abstracts reviewed, a total of 31 studies (n = 1597) were included in meta-analysis. Maxillomandibular advancement patients showed significant improvements in apnea-hypopnea index (AHI), respiratory disturbance index (RDI), SpO2 Nadir, Epworth sleepiness scale (ESS), and body-mass index (BMI) by -41.87/h [-49.86 to -33.89], -46.24/h [-62.18 to -30.29], 6.29% [3.42 to 12.08], -8.69 [-11.54 to -5.83], and -0.74 kg/m2 [-1.35 to -0.12], respectively. Sequelae with the greatest incidence were early lower facial numbness (83.40%), late lower facial numbness at less and greater than 1 year follow-up (66.51%, 32.73% respectively), and hardware removal (21.99%). There was a positive correlation between both preoperative BMI and length of hospital stay (r = 0.81, P = .052) and age and lower facial numbness (r = 0.42, P = .196). A negative correlation was found between Change in AHI and time to follow up (r = 0.75, P = .087). No major complications nor mortality were reported.

CONCLUSION

Maxillomandibular advancement has the highest success rate for obstructive sleep apnea among current surgical treatments, with most sequelae being transient. Early lower facial numbness should be highlighted preoperatively to ensure informed decision-making. Further research should be geared towards reducing this risk.

Obesity Surgery Mortality Risk Score as a Predictor for Intensive Care Unit Admission in Patients Undergoing Laparoscopic Bariatric Surgery

Background: Laparoscopic bariatric surgery provides many benefits including lower postoperative pain scores, reduced opioid consumption, shorter hospital stays, and improved quality of recovery. However, the anaesthetic management of obese patients requires caution in determining postoperative risk and in planning adequate postoperative pathways. Currently, there are no specific indications for intensive care unit (ICU) admission in this surgical population and most decisions are made on a case-by-case basis. The aim of this study is to investigate whether Obesity Surgery Mortality Risk Score (OS-MRS) is able to predict ICU admission in patients undergoing laparoscopic bariatric surgery (LBS). Methods: We retrospectively reviewed data of patients who underwent LBS during a 2-year period (2017-2019). The collected data included demographics, comorbidities and surgery-related variables. Postoperative ICU admission was decided via bariatric anaesthesiologists' evaluations, based on the high risk of postoperative cardiac or respiratory complications. Anaesthesia protocol was standardized. Logistic regression was used for statistical analysis. Results: ICU admission was required in 2% (n = 15) of the 763 patients. The intermediate risk group of the OS-MRS was detected in 84% of patients, while the American Society of Anaesthesiologists class III was reported in 80% of patients. A greater OS-MRS (p = 0.01), advanced age (p = 0.04), male gender (p = 0.001), longer duration of surgery (p = 0.0001), increased number of patient comorbidities (p = 0.002), and previous abdominal surgeries (p = 0.003) were predictive factors for ICU admission. Conclusions: ICU admission in obese patients undergoing LBS is predicted by OS-MRS together with age, male gender, number of comorbidities, previous abdominal surgeries, and duration of surgery.

Impact of 1-week preoperative auto-CPAP treatment on postoperative outcomes in patients undergoing heart valve replacement surgery: a prospective randomized controlled trial

Background

Whether preoperative continuous positive airway pressure (CPAP) treatment improves postoperative outcomes in patients undergoing cardiac valve replacement (CVR) remains unknown.

Hypothesis

This study was to evaluate the effects of 1-week perioperative auto-continuous positive airway pressure (CPAP) treatment on postoperative heart and pulmonary outcomes in patients with obstructive sleep apnea (OSA) and valvular heart disease.

Methods

Thirty-two patients with OSA and valvular heart disease were randomly assigned to 1-week CPAP (n = 15) group and non-CPAP treatments (n = 17) group. After the treatment, all patients underwent CVR surgery. The length of ICU and hospital stays, postoperative cardiac and respiratory complications were assessed and compared between the 2 groups.

Results

The results showed there was no significant difference in the baseline characteristics between the CPAP and non-CPAP treatment groups. The length of postoperative ICU and hospital stays, as well as the duration of mechanical ventilation were significantly reduced in the CPAP treatment group compared to the non-CPAP treatment group; however, there were no significant differences in cardiac complications (postoperative arrhythmias, pacemaker use, first dose of dopamine in the ICU, and first dose of dobutamine in the ICU), and respiratory complications (reintubation and pneumonia).

Conclusion

We concluded that in patients underwent CVR, preoperative use of auto-CPAP for OSA significantly decreased the duration of mechanical ventilation, and postoperative stays in the ICU and hospital.Clinical Trial Registration: https://ClinicalTrials.gov, identifier NCT03398733.

The effectiveness of positive airway pressure therapy in reducing postoperative adverse outcomes in surgical patients with obstructive sleep apnea: A systematic review and meta-analysis

IMPORTANCE

Obstructive sleep apnea (OSA) is prevalent in surgical patients and is associated with an increased risk of adverse perioperative events.

STUDY OBJECTIVE

To determine the effectiveness of positive airway pressure (PAP) therapy in reducing the risk of postoperative complications in patients with OSA undergoing surgery.

DESIGN

Systematic review and meta-analysis searching Medline and other databases from inception to October 17, 2021. The search terms included: "positive airway pressure," "surgery," "post-operative," and "obstructive sleep apnea." The inclusion criteria were: 1) adult patients with OSA undergoing surgery; (2) patients using preoperative and/or postoperative PAP; (3) at least one postoperative outcome reported; (4) control group (patients with OSA undergoing surgery without preoperative and/or postoperative PAP therapy); and (5) English language articles.

PATIENTS

Twenty-seven studies included 30,514 OSA patients undergoing non-cardiac surgery and 837 OSA patients undergoing cardiac surgery.

INTERVENTION

PAP therapy MAIN RESULTS: In patients with OSA undergoing non-cardiac surgery, PAP therapy was associated with a decreased risk of postoperative respiratory complications (2.3% vs 3.6%; RR: 0.72, 95% CI: 0.51-1.00, asymptotic P = 0.05) and unplanned ICU admission (0.12% vs 4.1%; RR: 0.44, 95% CI: 0.19-0.99, asymptotic P = 0.05). No significant differences were found for all-cause complications (11.6% vs 14.4%; RR: 0.89, 95% CI: 0.74-1.06, P = 0.18), postoperative cardiac and neurological complications, in-hospital length of stay, and in-hospital mortality between the two groups. In patients with OSA undergoing cardiac surgery, PAP therapy was associated with decreased postoperative cardiac complications (33.7% vs 50%; RR: 0.63, 95% CI: 0.51-0.77, P < 0.0001), and postoperative atrial fibrillation (40.1% vs 66.7%; RR: 0.59, 95% CI 0.45-0.77, P < 0.0001).

CONCLUSION

In patients with OSA undergoing non-cardiac surgery, PAP therapy was associated with a 28% reduction in the risk of postoperative respiratory complications and 56% reduction in unplanned ICU admission. In patients with OSA undergoing cardiac surgery, PAP therapy decreased the risk of postoperative cardiac complications and atrial fibrillation by 37% and 41%, respectively.

Enhanced recovery after bariatric surgery: an Italian consensus statement

Background

Enhanced recovery after bariatric surgery (ERABS) is an approach developed to improve outcomes in obese surgical patients. Unfortunately, it is not evenly implemented in Italy. The Italian Society for the Surgery of Obesity and Metabolic Diseases and the Italian Society of Anesthesia, Analgesia, Resuscitation and Intensive Care joined in drafting an official statement on ERABS.

Methods

To assess the effectiveness and safety of ERABS and to develop evidence-based recommendations with regard to pre-, intra-, and post-operative care for obese patients undergoing ERABS, a 13-member expert task force of surgeons and anesthesiologists from Italian certified IFSO center of excellence in bariatric surgery was established and a review of English-language papers conducted. Oxford 2011 Levels of Evidence and U.S. Preventive Services Task Force Grade Definitions were used to grade the level of evidence and the strength of recommendations, respectively. The supporting evidence and recommendations were reviewed and discussed by the entire group at meetings to achieve a final consensus.

Results

Compared to the conventional approach, ERABS reduces the length of hospital stay and does not heighten the risk of major post-operative complications, re-operations, and hospital re-admissions, nor does it increase the overall surgical costs. A total of 25 recommendations were proposed, covering pre-operative evaluation and care (7 items), intra-operative management (1 item, 11 sub-items), and post-operative care and discharge (6 items).

Conclusions

ERABS is an effective and safe approach. The recommendations allow the proper management of obese patients undergoing ERABS for a better outcome.

Improving Bed Utilization in a Cohort of Bariatric Surgical Patients Using a Perioperative Obstructive Sleep Apnea Treatment and Bed Triage Protocol

BACKGROUND

Postoperative bariatric management often includes high-intensity monitoring for respiratory complications since > 70% of patients have obstructive sleep apnea. Given the increasing number of bariatric surgeries, there is a need to determine safe and cost-effective processes for postoperative care.The objective of this study was to determine if a novel triage and perioperative management guideline reduces postoperative monitoring and costs following bariatric surgery.

METHODS

Using a pre-post design, this is a retrospective analysis of 501 patients who had bariatric surgery. Half the patients were managed with usual care, and the other half received obstructive sleep apnea screening and treatment of moderate/severe obstructive sleep apnea with perioperative continuous positive airway pressure. The intervention group was triaged preoperatively to a postoperative nursing location based on risk factors.

RESULTS

There were no significant differences in demographics, comorbidities, frequency, or severity of OSA between groups. In the intervention group, there were fewer admissions to the intensive care unit (2.0% vs 9.1%; p < 0.01) and high acuity unit (9.6% vs 18.3%; p < 0.01). The length of stay was shorter in the intervention group (1.3 vs 2.3 days; p < 0.01) with a 50% reduction in costs. There were no statistically significant differences in the incidence of postoperative respiratory and non-respiratory complications between the two groups.

CONCLUSIONS

Most postoperative bariatric surgery patients can be safely managed on the surgical ward with monitoring of routine vitals alone if patients with moderate/severe obstructive sleep apnea receive perioperative continuous positive airway pressure.

Anesthesia and Enhanced Recovery After Surgery in Bariatric Surgery

The Enhanced Recovery After Surgery Society published guidelines for bariatric surgery reviewing the evidence and providing specific care recommendations. These guidelines emphasize preoperative nutrition, multimodal analgesia, postoperative nausea and vomiting prophylaxis, anesthetic technique, nutrition, and mobilization. Several studies have since evaluated these pathways, showing them to be safe and effective at decreasing hospital length of stay and postoperative nausea and vomiting. This article emphasizes anesthetic management in the perioperative period and outlines future directions, including the application of Enhanced Recovery After Surgery principles in patients with extreme obesity, diabetes, and metabolic disease and standardization of the pathways to decrease heterogeneity.

Is Intensive Care Unit Monitoring Necessary After Maxillomandibular Advancement for Management of Obstructive Sleep Apnea?

PURPOSE

Maxillomandibular advancement (MMA) is an accepted treatment modality for obstructive sleep apnea. The purpose of this study was to evaluate the incidence of complications requiring an intensive care unit (ICU) level of care and the necessity of routine overnight ICU airway monitoring after MMA.

PATIENTS AND METHODS

This was a retrospective cohort study of patients undergoing MMA at Massachusetts General Hospital from 2003 to 2020. The primary predictor variable was postoperative admission to the ICU versus post anesthesia care unit (PACU) or ward. The primary outcome variable was grade IV or V complications as scored using the Clavien-Dindo classification system. The secondary outcome variables included postoperative SpO₂ nadir and length of hospital stay. Descriptive and bivariate statistics were computed to measure the association between complications and predictor variables.

RESULTS

The study sample consisted of 104 patients (74.0% male, mean age 37.6 ± 12.1 years), 61 of whom were admitted to the ICU (58.7%). During the initial 24 hours of airway monitoring, the mean SpO₂ nadir was 93.7 ± 2.59% for patients admitted to the ICU compared with 94.0 ± 6.56% for patients admitted to the PACU or ward (P = .862). Patients experienced 2 grade IV complications (1.92%) and no grade V complications, with no statistical association between complications and postoperative admission location (P = 1.000). Age (P = .002) and operative time (P = .046) were the only variables statistically associated with grade IV or V complications. There was no difference in length of hospital stay between patients admitted to the ICU (2.64 ± 1.37 days) versus PACU or ward (2.58 ± 1.62 days).

CONCLUSIONS

The incidence of complications requiring ICU-level care after MMA for obstructive sleep apnea is low. Additional studies are warranted to guide development of feasible, cost-effective perioperative protocols for patients undergoing MMA.

A Quality Improvement Project for Monitoring Surgical Patients With Obstructive Sleep Apnea

INTRODUCTION

Patients who have obstructive sleep apnea (OSA) are at a higher risk for opioid-induced respiratory depression postoperatively. Many patients who have OSA are not given a diagnosis before undergoing surgery and may not be monitored appropriately afterward.

PURPOSE

The purpose of this quality improvement project was to increase the number of preoperative patients screened for OSA and improve their postoperative monitoring through a novel OSA protocol order set through the implementation of evidence-based practices.

METHODS

Screening for OSA risk is performed preoperatively using the STOP-Bang instrument. High-risk patients, as well as patients with existing OSA, are monitored postoperatively using a bundle of evidence practices to identify early respiratory compromise. If respiratory events occur, a treatment intervention will be triggered.

OUTCOME

Postintervention chart reviews demonstrated 100% of the qualifying patients had OSA screening completed before surgery. The OSA protocol was ordered in 28 of the 100 charts reviewed. Patient harm may have been avoided through the implementation of the protocol's standing order for continuous positive airway pressure, which was triggered by respiratory events.

CONCLUSION

It is important to identify these high-risk patients before surgery through preoperative screening. These patients should be monitored closely postoperatively to identify early respiratory compromise.

Efficacy of patient selection criteria for obesity surgery in a non-high-dependency unit/intensive care unit facility

BACKGROUNDS

Publicly funded obesity surgery remains underfunded in Australia. One barrier to expansion is the perception that perioperative care requires critical care facilities. This study evaluates the effectiveness of patient selection criteria in avoiding unplanned patient transfer and adverse outcomes in obesity surgery performed at a facility without a high-dependency unit/intensive care unit (HDU/ICU).

METHODS

Retrospective analysis was performed on patients undergoing obesity surgery between January 2017 and March 2020 in a centre with specific screening criteria. Criteria included: body mass index <48 for males and <52 for females with up to three stable comorbidities from a selected list. Revision sleeve or bypass procedures were contraindicated. Primary outcome was patient transfer to our main campus. Secondary outcomes included return to theatre (RTT), readmission and death. Outcomes were compared to laparoscopic cholecystectomies (LC) performed at the same centre.

RESULTS

A total of 387 obesity surgery procedures were performed; 372 patients (96%) were discharged without complication. Fifteen (3.9%) were transferred to the main campus, eight were admitted to ICU and two required re-operation. Twelve (3.1%) were readmitted within 30 days of discharge, five required re-operation. Transfer, 30-day readmission and 30-day emergency department presentation rates were similar in comparison to LC. RTT during index admission (0.5% vs. 3.0%; p = 0.006) and during 30-day post-operative period (1.8% vs. 4.4%; p = 0.025) was lower in the obesity surgery group.

CONCLUSION

Carefully selected screening criteria allow obesity surgery to be performed at a well-supported non-HDU/ICU facility with few complications and acceptable rates of unplanned patient transfer.

Perioperative care of obstructive sleep apnea patients: A survey of European anesthesiologists

Background:

Obstructive sleep apnea (OSA) is prevalent in the surgical patient population and is associated with high risk of perioperative complications. There are limited guidelines and wide practice variations regarding the perioperative care of obese and OSA patients. This is a study of European anesthesiologists' clinical practice of perioperative care of OSA patients.

Methods:

This survey evaluated United Kingdom anesthesiologists' clinical practice of the perioperative care of OSA patients. Outcomes and variables were compared between 4100 anesthesiologists of different clinical experience and hospital settings.

Results:

Approximately 45% of respondents manage OSA patients rarely, 42% occasionally, and 13% regularly. Most respondents order OSA screening tests if patients have tonsillar hypertrophy, head/neck tumor, BMI >35, increased neck circumference, craniofacial anomaly, and right-sided electrocardiography (ECG) anomaly. Majority request preoperative polysomnography, ECG, overnight pulse oximetry, and arterial blood gas analysis. Majority recommend preoperative weight loss, optimisation, smoking cessation, reduction of substance use, and regular mask-CPAP use. Majority consider endoscopy, and ophthalmology as appropriate day case procedures, but not laparoscopy. Majority postpone elective airway, laparoscopic, laparotomy, and head/neck surgery; if patients are not optimized preoperatively. For major surgery, combined general + neuraxial anesthesia was ranked as 3^rd option. For major limb surgery, neuraxial anesthesia without sedation was ranked as 1^st option, nerve block without sedation was ranked 2^nd, and general anesthesia + nerve block was ranked 3^rd or 4^th. At anesthesia emergence, majority ensure that patients have normal consciousness, respiration and neuromuscular function. Majority ensure postoperative oximetry, telemetry, and oxygen supplementation.

Conclusion:

This study highlights variations in anesthesiologists' perioperative care of OSA patients; even in developed countries with advanced medical training and standards. The study outcomes will improve perioperative care of OSA patients.

Clinical Practice Guidelines for the Perioperative Nutrition, Metabolic, and Nonsurgical Support of Patients Undergoing Bariatric Procedures - 2019 Update: Cosponsored by American Association of Clinical Endocrinologists/American College of Endocrinology, The Obesity Society, American Society for Metabolic and Bariatric Surgery, Obesity Medicine Association, and American Society of Anesthesiologists

OBJECTIVE

The development of these updated clinical practice guidelines (CPGs) was commissioned by the American Association of Clinical Endocrinologists (AACE), The Obesity Society (TOS), American Society for Metabolic and Bariatric Surgery (ASMBS), Obesity Medicine Association (OMA), and American Society of Anesthesiologists (ASA) Boards of Directors in adherence with the AACE 2017 protocol for standardized production of CPGs, algorithms, and checklists.

METHODS

Each recommendation was evaluated and updated based on new evidence from 2013 to the present and subjective factors provided by experts.

RESULTS

New or updated topics in this CPG include: contextualization in an adiposity-based chronic disease complications-centric model, nuance-based and algorithm/checklist-assisted clinical decision-making about procedure selection, novel bariatric procedures, enhanced recovery after bariatric surgery protocols, and logistical concerns (including cost factors) in the current health care arena. There are 85 numbered recommendations that have updated supporting evidence, of which 61 are revised and 12 are new. Noting that there can be multiple recommendation statements within a single numbered recommendation, there are 31 (13%) Grade A, 42 (17%) Grade B, 72 (29%) Grade C, and 101 (41%) Grade D recommendations. There are 858 citations, of which 81 (9.4%) are evidence level (EL) 1 (highest), 562 (65.5%) are EL 2, 72 (8.4%) are EL 3, and 143 (16.7%) are EL 4 (lowest).

CONCLUSIONS

Bariatric procedures remain a safe and effective intervention for higher-risk patients with obesity. Clinical decision-making should be evidence based within the context of a chronic disease. A team approach to perioperative care is mandatory, with special attention to nutritional and metabolic issues.

Clinical practice guidelines for the perioperative nutrition, metabolic, and nonsurgical support of patients undergoing bariatric procedures - 2019 update: cosponsored by American Association of Clinical Endocrinologists/American College of Endocrinology, The Obesity Society, American Society for Metabolic & Bariatric Surgery, Obesity Medicine Association, and American Society of Anesthesiologists

OBJECTIVE

The development of these updated clinical practice guidelines (CPG) was commissioned by the American Association of Clinical Endocrinologists, The Obesity Society, the American Society of Metabolic and Bariatric Surgery, the Obesity Medicine Association, and the American Society of Anesthesiologists boards of directors in adherence to the American Association of Clinical Endocrinologists 2017 protocol for standardized production of CPG, algorithms, and checklists.

METHODS

Each recommendation was evaluated and updated based on new evidence from 2013 to the present and subjective factors provided by experts.

RESULTS

New or updated topics in this CPG include contextualization in an adiposity-based, chronic disease complications-centric model, nuance-based, and algorithm/checklist-assisted clinical decision-making about procedure selection, novel bariatric procedures, enhanced recovery after bariatric surgery protocols, and logistical concerns (including cost factors) in the current healthcare arena. There are 85 numbered recommendations that have updated supporting evidence, of which 61 are revised and 12 are new. Noting that there can be multiple recommendation statements within a single numbered recommendation, there are 31 (13%) Grade A, 42 (17%) Grade B, 72 (29%) Grade C, and 101 (41%) Grade D recommendations. There are 858 citations, of which 81 (9.4%) are evidence level (EL) 1 (highest), 562 (65.5%) are EL 2, 72 (8.4%) are EL 3, and 143 (16.7%) are EL 4 (lowest).

CONCLUSIONS

Bariatric procedures remain a safe and effective intervention for higher-risk patients with obesity. Clinical decision-making should be evidence-based within the context of a chronic disease. A team approach to perioperative care is mandatory with special attention to nutritional and metabolic issues.

Continuous Positive Airway Pressure Mitigates Opioid-induced Worsening of Sleep-disordered Breathing Early after Bariatric Surgery

BACKGROUND

Bariatric surgery patients are vulnerable to sleep-disordered breathing (SDB) early after recovery from surgery and anesthesia. The authors hypothesized that continuous positive airway pressure (CPAP) improves postoperative oxygenation and SDB and mitigates opioid-induced respiratory depression.

METHODS

In a randomized crossover trial, patients after bariatric surgery received 30% oxygen in the postanesthesia care unit (PACU) under two conditions: atmospheric pressure and CPAP (8 to 10 cm H2O). During 1 h of each treatment, breathing across cortical arousal states was analyzed using polysomnography and spirometry. Arousal state and respiratory events were scored in accordance with American Academy of Sleep Medicine guidelines. Data on opioid boluses in the PACU were collected. The primary and secondary outcomes were the apnea hypopnea index (AHI) and apnea after self-administration of opioids in the PACU. Linear mixed model analysis was used to compare physiologic measures of breathing.

RESULTS

Sixty-four percent of the 33 patients with complete postoperative polysomnography data demonstrated SDB (AHI greater than 5/h) early after recovery from anesthesia. CPAP treatment decreased AHI (8 ± 2/h vs. 25 ± 5/h, P < 0.001), decreased oxygen desaturations (5 ± 10/h vs. 16 ± 20/h, P < 0.001), and increased the mean oxygen saturation by 3% (P = 0.003). CPAP significantly decreased the respiratory-depressant effects observed during wakefulness-sleep transitions without affecting hemodynamics. The interaction effects between CPAP treatment and opioid dose for the dependent variables AHI (P < 0.001), inspiratory flow (P = 0.002), and minute ventilation (P = 0.015) were significant.

CONCLUSIONS

This pharmacophysiologic interaction trial shows that supervised CPAP treatment early after surgery improves SDB and ameliorates the respiratory-depressant effects of opioids without undue hemodynamic effects.

A Brief Review of Non-invasive Monitoring of Respiratory Condition for Extubated Patients with or at Risk for Obstructive Sleep Apnea after Surgery

Obstructive sleep apnea (OSA) is one of the important risk factors contributing to postoperative airway complications. OSA alters the respiratory physiology and increases the sensitivity of muscle tone of the upper airway after surgery to residual anesthetic medication. In addition, the prevalence of OSA was reported to be much higher among surgical patients than the general population. Therefore, appropriate monitoring to detect early respiratory impairment in postoperative extubated patients with possible OSA is challenging. Based on the comprehensive clinical observation, several equipment have been used for monitoring the respiratory conditions of OSA patients after surgery, including the continuous pulse oximetry, capnography, photoplethysmography (PPG), and respiratory volume monitor (RVM). To date, there has been no consensus on the most suitable device as a recommended standard of care. In this review, we describe the advantages and disadvantages of some possible monitoring strategies under certain clinical conditions. According to the literature, the continuous pulse oximetry, with its high sensitivity, is still the most widely used device. It is also cost-effective and convenient to use but has low specificity and does not reflect ventilation. Capnography is the most widely used device for detection of hypoventilation, but it may not provide reliable data for extubated patients. Even normal capnography cannot exclude the existence of hypoxia. PPG shows the state of both ventilation and oxygenation, but its sensitivity needs further improvement. RVM provides real-time detection of hypoventilation, quantitative precise demonstration of respiratory rate, tidal volume, and MV for extubated patients, but no reflection of oxygenation. Altogether, the sole use of any of these devices is not ideal for monitoring of extubated patients with or at risk for OSA after surgery. However, we expect that the combined use of continuous pulse oximetry and RVM may be promising for these patients due to their complementary function, which need further study.

A Brief Review of Non-invasive Monitoring of Respiratory Condition for Extubated Patients with or at Risk for Obstructive Sleep Apnea after Surgery

Obstructive sleep apnea (OSA) is one of the important risk factors contributing to postoperative airway complications. OSA alters the respiratory physiology and increases the sensitivity of muscle tone of the upper airway after surgery to residual anesthetic medication. In addition, the prevalence of OSA was reported to be much higher among surgical patients than the general population. Therefore, appropriate monitoring to detect early respiratory impairment in postoperative extubated patients with possible OSA is challenging. Based on the comprehensive clinical observation, several equipment have been used for monitoring the respiratory conditions of OSA patients after surgery, including the continuous pulse oximetry, capnography, photoplethysmography (PPG), and respiratory volume monitor (RVM). To date, there has been no consensus on the most suitable device as a recommended standard of care. In this review, we describe the advantages and disadvantages of some possible monitoring strategies under certain clinical conditions. According to the literature, the continuous pulse oximetry, with its high sensitivity, is still the most widely used device. It is also cost-effective and convenient to use but has low specificity and does not reflect ventilation. Capnography is the most widely used device for detection of hypoventilation, but it may not provide reliable data for extubated patients. Even normal capnography cannot exclude the existence of hypoxia. PPG shows the state of both ventilation and oxygenation, but its sensitivity needs further improvement. RVM provides real-time detection of hypoventilation, quantitative precise demonstration of respiratory rate, tidal volume, and MV for extubated patients, but no reflection of oxygenation. Altogether, the sole use of any of these devices is not ideal for monitoring of extubated patients with or at risk for OSA after surgery. However, we expect that the combined use of continuous pulse oximetry and RVM may be promising for these patients due to their complementary function, which need further study.