Role of continuous pulse oximetry and capnography monitoring in the prevention of postoperative respiratory failure, postoperative opioid-induced respiratory depression and adverse outcomes on hospital wards: A systematic review and meta-analysis.

OBJECTIVE: The current standards of postoperative respiratory monitoring on medical-surgical floors involve spot-pulse oximetry checks every 4-8 h, which can miss the opportunity to detect prolonged hypoxia and acute hypercapnia. Continuous respiratory monitoring can recognize acute respiratory depression episodes; however, the existing evidence is limited. We sought to review the current evidence on the effectiveness of continuous pulse oximetry (CPOX) with and without capnography versus routine monitoring and their effectiveness for detecting postoperative respiratory failure, opioid-induced respiratory depression, and preventing downstream adverse events. METHODS: We performed a systematic literature search on Ovid Medline, Embase, and Cochrane Library databases for articles published between 1990 and April 2023. The study protocol was registered in Prospero (ID: 439467), and PRISMA guidelines were followed. The NIH quality assessment tool was used to assess the quality of the studies. Pooled analysis was conducted using the software R version 4.1.1 and the package meta. The stability of the results was assessed using sensitivity analysis. DESIGN: Systematic Review and Meta-Analysis. SETTING: Postoperative recovery area. PATIENTS: 56,538 patients, ASA class II to IV, non-invasive respiratory monitoring, and post-operative respiratory depression. INTERVENTIONS: Continuous pulse oximetry with or without capnography versus routine monitoring. MEASUREMENTS: Respiratory rate, oxygen saturation, adverse events, and rescue events. RESULTS: 23 studies (17 examined CPOX without capnography and 5 examined CPOX with capnography) were included in this systematic review. CPOX was better at recognizing desaturation (SpO2 < 90%) OR: 11.94 (95% CI: 6.85, 20.82; p < 0.01) compared to standard monitoring. No significant differences were reported for ICU transfer, reintubation, and non-invasive ventilation between the two groups. CONCLUSIONS: Oxygen desaturation was the only outcome better detected with CPOX in postoperative patients in hospital wards. These comparisons were limited by the small number of studies that could be pooled for each outcome and the heterogeneity between the studies.

Patient Characteristics and Clinical and Economic Outcomes Associated with Unplanned Medical and Surgical Intensive Care Unit Admissions: A Retrospective Analysis.

Purpose: To characterize medical and surgical patient characteristics, as well as clinical and economic outcomes, associated with unplanned intensive care unit (ICU) admissions. Patients and Methods: This was a retrospective matched cohort analysis that utilized the PINC AITM Healthcare Database, which collects deidentified data from 25% of United States (US) hospital admissions. Discharge records were assessed for medical and surgical admissions in 2021. An unplanned ICU admission was defined as direct transfer from a medical, surgical, or telemetry unit to the ICU. Patients with and without an unplanned ICU admission were 1:1 propensity score matched. Differences between patients with and without unplanned ICU admissions were assessed using two-sample t-tests for continuous measures and Chi-square tests for categorical measures. Results: A total of 3,807,124 qualifying admissions were identified. Medical admissions with unplanned ICU transfers were more likely to be urgent/emergent (odds ratio [OR] 2.9, 95% confidence interval [CI 2.7-3.0], p<0.0001), with patient characteristics including male sex (1.4, [1.4-1.4], p<0.0001), obesity (1.7, [1.6-1.7], p<0.0001), and increased Charlson Comorbidity Index (CCI=1: 1.8, [1.8-1.9], p<0.0001; CCI≥5: 3.2, [3.1-3.3], p<0.0001). Surgical admissions with unplanned ICU transfers were more likely to be urgent/emergent (3.1, [2.9-3.2], p<0.0001) and with patients of higher CCI (2.5, [2.3-2.6], p<0.0001 to a CCI of≥5 (7.9, [7.4-8.4], p<0.0001). Between matched medical patients, mean differences in length of stay, cost, and mortality were 4.1 days (p<0.0001), $13,424 (p<0.0001), and 21% (p<0.0001), respectively. Between matched surgical patients, mean differences in these outcomes were 6.4 days (p<0.0001), $21,448 (p<0.0001), and 14% (p<0.0001), respectively. Conclusion: Emergency care in patients with a higher co-morbid burden is more likely to lead to unplanned ICU admission, putting patients at a significantly increased chance of mortality, longer length of stay, and increased costs. Improving care and monitoring of patients outside the ICU may help detect early changes in pathophysiology and enable early intervention.

Unrecognized Pulmonary Hypertension in Non-Cardiac Surgical Patients: At-Risk Populations, Preoperative Evaluation, Intraoperative Management and Postoperative Complications.

Pulmonary hypertension is a well-established independent risk factor for perioperative complications after elective non-cardiac surgery. Patients undergoing cardiac surgery are routinely evaluated for the presence of pulmonary hypertension in the preoperative period. Better monitoring in the postoperative critical care setting leads to more efficient management of potential complications. Data among patients with pulmonary hypertension undergoing elective non-cardiac surgery are scant. Moreover, the condition may be unidentified at the time of surgery. Also, monitoring after non-cardiac surgery can be very limited in the PACU setting, as opposed to the critical care setting. All these factors can result in a higher postoperative complication rate and poor outcomes.

Obesity-associated sleep hypoventilation and increased adverse postoperative bariatric surgery outcomes in a large clinical retrospective cohort.

STUDY OBJECTIVES: Although obesity hypoventilation syndrome (OHS) is associated with increased morbidity and mortality, post-bariatric surgery OHS risk remains unclear due to often nonsystematic OHS assessments. METHODS: We leverage a clinical cohort with nocturnal CO2 monitoring during polysomnography to address the hypothesis that patients with obesity-associated sleep hypoventilation (OaSH; ie, stage II OHS) have increased adverse postoperative bariatric surgery outcomes. We retrospectively analyzed data from patients undergoing pre-bariatric surgery polysomnography at the Cleveland Clinic from 2011-2018. OaSH was defined by body mass index ≥ 30 kg/m2 and either polysomnography-based end-tidal CO2 ≥ 45 mmHg or serum bicarbonate ≥ 27 mEq/L. Outcomes considered were as follows: intensive care unit stay, intubation, tracheostomy, discharge disposition other than home or 30-day readmission individually and as a composite, and all-cause mortality. Two-sample t test or Wilcoxon rank-sum test for continuous variables and chi-square or Fisher's exact test for categorical variables were used for OaSH vs non-OaSH comparisons. All-cause mortality was compared using Kaplan-Meier estimation and Cox proportional hazards models. RESULTS: The analytic sample (n = 1,665) was aged 45.2 ± 12 years, 20.4% were male, had a body mass index of 48.7 ± 9 kg/m2, and 63.6% were White. OaSH prevalence was 68.5%. OaSH patients were older and more likely to be male with a higher BMI, apnea-hypopnea index, and glycated hemoglobin. The composite outcome was higher in OaSH vs non-OaSH patients (18.9% vs 14.3%, P = .021). Although some individual outcomes were respectively higher in OaSH vs non-OaSH patients, differences were not statistically significant: intubation (1.5% vs 1.3%, P = .81) and 30-day readmission (13.8% vs 11.3%, P = .16). Long-term mortality (median follow-up: 22.9 months) was not significantly different between groups, likely due to overall low event rate (hazard ratio = 1.39, 95% confidence interval: 0.56, 3.42). CONCLUSIONS: In this largest sample to date of systematically phenotyped OaSH in a bariatric surgery cohort, we identify increased postoperative morbidity in those with sleep-related hypoventilation in stage II OHS when a composite outcome was considered, but individual contributors of intubation, intensive care unit admission, and hospital length of stay were not increased. Further study is needed to identify whether perioperative treatment of OaSH improves post-bariatric surgery outcomes. CITATION: Chindamporn P, Wang L, Bena J, et al. Obesity-associated sleep hypoventilation and increased adverse postoperative bariatric surgery outcomes in a large clinical retrospective cohort. J Clin Sleep Med. 2022;18(12):2793-2801.

Utilization and outcomes of aortic valve replacements (from the United States readmissions database).

Study objective: Assess the utilization of aortic valve replacements (AVR). Design: Retrospective analysis of the Nationwide Readmissions Database (2016-2018). Setting: Nationwide. Participants: Heart failure patients with concomitant aortic stenosis (CHF + AS cohort) or aortic stenosis with aortic regurgitation (CHF + AS+AR cohort). Interventions: Transcatheter aortic valve implantation (TAVI), surgical aortic valve replacement (SAVR), no-AVR. Main outcome measures: Utilization of treatment interventions. Results: In the CHF + AS cohort, TAVI, SAVR and no-AVR were done in 9.3 %, 10.8 % and 79.9 % of patients respectively. Similarly, majority of CHF + AS+AR patients were managed with no-AVR (53.2 %). Of patients managed with no-AVR in the first six months of each year, only 7.9 % of CHF + AS and 11.8 % of CHF + AS+AR patients underwent AVR in the subsequent six months of the year. No-AVR patients had worse short-term outcomes in comparison to AVR recipients. Conclusion: More studies are needed to understand the timing, indications and utilization of AVR in this population.

Obesity and Obesity Hypoventilation, Sleep Hypoventilation, and Postoperative Respiratory Failure.

Obesity hypoventilation syndrome (OHS) is considered as a diagnosis in obese patients (body mass index [BMI] ≥30 kg/m2) who also have sleep-disordered breathing and awake diurnal hypercapnia in the absence of other causes of hypoventilation. Patients with OHS have a higher burden of medical comorbidities as compared to those with obstructive sleep apnea (OSA). This places patients with OHS at higher risk for adverse postoperative events. Obese patients and those with OSA undergoing elective noncardiac surgery are not routinely screened for OHS. Screening for OHS would require additional preoperative evaluation of morbidly obese patients with severe OSA and suspicion of hypoventilation or resting hypoxemia. Cautious selection of the type of anesthesia, use of apneic oxygenation with high-flow nasal cannula during laryngoscopy, better monitoring in the postanesthesia care unit (PACU) can help minimize adverse perioperative events. Among other risk-reduction strategies are proper patient positioning, especially during intubation and extubation, multimodal analgesia, and cautious use of postoperative supplemental oxygen.

Obesity Hypoventilation: Traditional Versus Nontraditional Populations.

Obesity hypoventilation syndrome is the most frequent cause of chronic hypoventilation and is increasingly more common with rising obesity rates. It leads to considerable morbidity and mortality, particularly when not recognized and treated adequately. Long-term nocturnal noninvasive ventilation is the mainstay of treatment but evidence suggests that CPAP may be effective in stable patients. Specific perioperative management is required to reduce complications. Some unique syndromes associated with obesity and hypoventilation include rapid-onset obesity with hypoventilation, hypothalamic, autonomic dysregulation (ROHHAD), and Prader-Willi syndrome. Congenital central hypoventilation syndrome (early or late-onset) is a genetic disorder resulting in hypoventilation. Several acquired causes of chronic central hypoventilation also exist. A high level of clinical suspicion is required to appropriately diagnose and manage affected patients.

Prediction of Opioid-Induced Respiratory Depression on Inpatient Wards Using Continuous Capnography and Oximetry: An International Prospective, Observational Trial.

BACKGROUND: Opioid-related adverse events are a serious problem in hospitalized patients. Little is known about patients who are likely to experience opioid-induced respiratory depression events on the general care floor and may benefit from improved monitoring and early intervention. The trial objective was to derive and validate a risk prediction tool for respiratory depression in patients receiving opioids, as detected by continuous pulse oximetry and capnography monitoring. METHODS: PRediction of Opioid-induced respiratory Depression In patients monitored by capnoGraphY (PRODIGY) was a prospective, observational trial of blinded continuous capnography and oximetry conducted at 16 sites in the United States, Europe, and Asia. Vital signs were intermittently monitored per standard of care. A total of 1335 patients receiving parenteral opioids and continuously monitored on the general care floor were included in the analysis. A respiratory depression episode was defined as respiratory rate ≤5 breaths/min (bpm), oxygen saturation ≤85%, or end-tidal carbon dioxide ≤15 or ≥60 mm Hg for ≥3 minutes; apnea episode lasting >30 seconds; or any respiratory opioid-related adverse event. A risk prediction tool was derived using a multivariable logistic regression model of 46 a priori defined risk factors with stepwise selection and was internally validated by bootstrapping. RESULTS: One or more respiratory depression episodes were detected in 614 (46%) of 1335 general care floor patients (43% male; mean age, 58 ± 14 years) continuously monitored for a median of 24 hours (interquartile range [IQR], 17-26). A multivariable respiratory depression prediction model with area under the curve of 0.740 was developed using 5 independent variables: age ≥60 (in decades), sex, opioid naivety, sleep disorders, and chronic heart failure. The PRODIGY risk prediction tool showed significant separation between patients with and without respiratory depression (P < .001) and an odds ratio of 6.07 (95% confidence interval [CI], 4.44-8.30; P < .001) between the high- and low-risk groups. Compared to patients without respiratory depression episodes, mean hospital length of stay was 3 days longer in patients with ≥1 respiratory depression episode (10.5 ± 10.8 vs 7.7 ± 7.8 days; P < .0001) identified using continuous oximetry and capnography monitoring. CONCLUSIONS: A PRODIGY risk prediction model, derived from continuous oximetry and capnography, accurately predicts respiratory depression episodes in patients receiving opioids on the general care floor. Implementation of the PRODIGY score to determine the need for continuous monitoring may be a first step to reduce the incidence and consequences of respiratory compromise in patients receiving opioids on the general care floor.

Use of adaptive servo ventilation therapy as treatment of sleep-disordered breathing and heart failure: a systematic review and meta-analysis.

PURPOSE: Adaptive servoventilation (ASV) has been reported to show improvement in patients with sleep-disordered breathing (SDB) and heart failure (HF); however, its role as a second-line or adjunctive treatment is not clear. We conducted a systematic review and meta-analysis of new existing data including cardiac mechanistic factor, geometry, and cardiac biomarkers. METHODS: We systematically searched for randomized controlled trials (RCTs) and cohort studies that assessed the efficacy or effectiveness of ASV compared to conventional treatments for SDB and HF in five research databases from their inception to November 2018. Random-effects meta-analyses using the inverse variance method and stratified by study design were performed. RESULTS: We included 15 RCTs (n = 859) and 5 cohorts (n = 162) that met our inclusion criteria. ASV significantly improved left ventricular ejection fraction (LVEF) in cohorts (MD 6.96%, 95% CI 2.58, 11.34, p = 0.002), but not in RCTs. Also, the ASV group had significantly lower apnea-hypopnea index (AHI) in both cohorts (MD - 26.02, 95% CI - 36.94, - 15.10, p < 0.00001) and RCTs (MD - 21.83, 95% CI - 28.17, - 15.49, p < 0.00001). ASV did not significantly decrease the E/e' ratio in RCTs or in cohorts. Finally, ASV significantly decreased brain natriuretic peptide (BNP) in the cohorts (SMD - 121.99, CI 95% - 186.47, - 57.51, p = 0.0002) but not in RCTs. ASV did not have a significant effect on systolic blood pressure, diastolic blood pressure, and cardiac diameters. CONCLUSIONS: ASV therapy is associated with improvements of AHI in comparison to alternative treatments in patients with SDB and HF. ASV did not improve LVEF or E/e' ratios in randomized trials; other intermediate outcomes did not improve significantly.

Evaluation and Management of Obesity Hypoventilation Syndrome. An Official American Thoracic Society Clinical Practice Guideline.

Background: The purpose of this guideline is to optimize evaluation and management of patients with obesity hypoventilation syndrome (OHS).Methods: A multidisciplinary panel identified and prioritized five clinical questions. The panel performed systematic reviews of available studies (up to July 2018) and followed the Grading of Recommendations, Assessment, Development, and Evaluation evidence-to-decision framework to develop recommendations. All panel members discussed and approved the recommendations.Recommendations: After considering the overall very low quality of the evidence, the panel made five conditional recommendations. We suggest that: 1) clinicians use a serum bicarbonate level <27 mmol/L to exclude the diagnosis of OHS in obese patients with sleep-disordered breathing when suspicion for OHS is not very high (<20%) but to measure arterial blood gases in patients strongly suspected of having OHS, 2) stable ambulatory patients with OHS receive positive airway pressure (PAP), 3) continuous positive airway pressure (CPAP) rather than noninvasive ventilation be offered as the first-line treatment to stable ambulatory patients with OHS and coexistent severe obstructive sleep apnea, 4) patients hospitalized with respiratory failure and suspected of having OHS be discharged with noninvasive ventilation until they undergo outpatient diagnostic procedures and PAP titration in the sleep laboratory (ideally within 2-3 mo), and 5) patients with OHS use weight-loss interventions that produce sustained weight loss of 25% to 30% of body weight to achieve resolution of OHS (which is more likely to be obtained with bariatric surgery).Conclusions: Clinicians may use these recommendations, on the basis of the best available evidence, to guide management and improve outcomes among patients with OHS.

Predictive Value of Stress Testing, Revised Cardiac Risk Index, and Functional Status in Patients Undergoing Noncardiac Surgery.

OBJECTIVE: Patients undergoing noncardiac surgery are at risk for postoperative cardiovascular complications. Literature regarding the ability of the Revised Cardiac Risk Index (RCRI), functional capacity, and stress testing to predict perioperative cardiac events is scarce. The authors examined the association of these parameters with perioperative cardiac events and their additive ability to predict these outcomes. DESIGN: This was a single-center retrospective study conducted at the Cleveland Clinic. SETTING: Hospital. PARTICIPANTS: Patients undergoing noncardiac surgery. INTERVENTION: Patients underwent stress testing. MEASUREMENTS AND MAIN RESULTS: The primary outcome of interest was major adverse cardiac events (MACE). The study cohort included 509 patients with a predominantly good functional status, as defined by estimated metabolic equivalents (METSe), which was ≥4 in 83% of the patients. The addition of preoperative stress testing, when indicated based on the RCRI and functional class limitation, only modestly improved discrimination of risk for postoperative outcomes (METSe + RCRI + positive stress test-C statistic 0.77 for MACE; 0.84 for 1-year mortality) compared with the combination of functional capacity (METSe) and RCRI (C statistic 0.70 for MACE; 0.79 for 1-year mortality). A surprisingly high prevalence of false negative stress tests (negative stress tests in patients who later had presence of obstructive coronary disease on angiography) was noted, but the C statistic for MACE remained unchanged, even when no false negative results were assumed. CONCLUSIONS: In a cohort of patients with predominantly good functional status and intermediate-to-high RCRI scores, addition of a preoperative stress test was of only moderate value in predicting postoperative cardiovascular outcomes compared with a combination of functional class and RCRI.

The role of B-type natriuretic peptide in diagnosing acute decompensated heart failure in chronic kidney disease patients.

INTRODUCTION: Chronic kidney disease (CKD) and congestive heart failure (CHF) patients have higher serum B-type natriuretic peptide (BNP), which alters the test interpretation. We aim to define BNP cutoff levels to diagnose acute decompensated heart failure (ADHF) in CKD according to CHF subtype: heart failure with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HFrEF). MATERIAL AND METHODS: We reviewed 1,437 charts of consecutive patients who were admitted for dyspnea. We excluded patients with normal kidney function, without measured BNP, echocardiography, or history of CHF. BNP cutoff values to diagnose ADHF for CKD stages according to CHF subtype were obtained for the highest pair of sensitivity (Sn) and specificity (Sp). We calculated positive and negative likelihood ratios (LR+ and LR-, respectively), and diagnostic odds ratios (DOR), as well as the area under the receiver operating characteristic curves (AUC) for BNP. RESULTS: We evaluated a cohort of 348 consecutive patients: 152 had ADHF, and 196 had stable CHF. In those with HFpEF with CKD stages 3-4, BNP < 155 pg/ml rules out ADHF (Sn90%, LR- = 0.26 and DOR = 5.75), and BNP > 670 pg/ml rules in ADHF (Sp90%, LR+ = 4 and DOR = 6), with an AUC = 0.79 (95% CI: 0.71-0.87). In contrast, in those with HFrEF with CKD stages 3-4, BNP < 412.5 pg/ml rules out ADHF (Sn90%, LR- = 0.19 and DOR = 9.37), and BNP > 1166.5 pg/ml rules in ADHF (Sp87%, LR+ = 3.9 and DOR = 6.97) with an AUC = 0.78 (95% CI: 0.69-0.86). All LRs and DOR were statistically significant. CONCLUSIONS: BNP cutoff values for the diagnosis of ADHF in HFrEF were higher than those in HFpEF across CKD stages 3-4, with moderate discriminatory diagnostic ability.