The Role of Obstructive Sleep Apnea in Hypercapnic Respiratory Failure Identified in Critical Care, Inpatient, and Outpatient Settings

An emerging body of literature describes the prevalence and consequences of hypercapnic respiratory failure. While device qualifications, documentation practices, and previously performed clinical studies often encourage conceptualizing patients as having a single "cause" of hypercapnia, many patients encountered in practice have several contributing conditions. Physiologic and epidemiologic data suggest that sleep-disordered breathing-particularly obstructive sleep apnea (OSA)-often contributes to the development of hypercapnia. In this review, the authors summarize the frequency of contributing conditions to hypercapnic respiratory failure among patients identified in critical care, emergency, and inpatient settings with an aim toward understanding the contribution of OSA to the development of hypercapnia.

The association of weight loss from anti-obesity medications or bariatric surgery and apnea-hypopnea index in obstructive sleep apnea

INTRODUCTION

Weight loss is recommended for individuals with obstructive sleep apnea (OSA) and overweight or obesity, but there is limited evidence to guide the selection of weight management strategies for patients who do not lose sufficient weight with diet and lifestyle changes. We evaluated the relationship between weight loss caused by pharmacologic or surgical interventions and subsequent improvement in OSA by the apnea-hypopnea index (AHI).

METHODS

PubMed, Cochrane CENTRAL, and EMBASE were searched for randomized trials comparing pharmacologic or surgical obesity interventions to usual care, placebo, or no treatment in adults with OSA. The association between percentage weight loss and AHI change between randomization and last follow-up was evaluated using meta-regression.

PROSPERO

CRD42022378853.

RESULTS

Ten eligible trials (n = 854 patients) were included. Four (n = 211) assessed bariatric surgery, and 6 (n = 643) assessed pharmacologic interventions over a median follow-up of 13 months (interquartile range 6-26 months). The linear best estimate of the change in AHI is 0.45 events per hour (95% Confidence Interval 0.18 to 0.73 events per hour) for every 1% body weight lost.

CONCLUSIONS

Weight loss caused by medication or surgery caused a proportionate improvement of the AHI. Providers could consider extrapolating from this relationship when advising patients of the expected effects of other pharmacologic or surgical interventions without direct evidence in OSA.

Predictors of Initial CPAP Prescription and Subsequent Course with CPAP in Patients with Central Sleep Apneas at a Single Center

PURPOSE

Guidelines recommend considering an initial trial of continuous positive airway pressure (CPAP) to treat central sleep apnea (CSA). However, practice patterns vary widely. This study investigated predictors for an initial trial of CPAP in patients with central apneas and whether those factors predict adequate treatment response in patients receiving an initial CPAP trial.

METHODS

Charts of patients receiving a diagnostic code for CSA following a sleep study during 2016-2018 at a single center were reviewed. Patient factors, initial treatment prescriptions, and subsequent changes to therapy were extracted from electronic health records. Regression models were used to estimate factors associated with an initial CPAP prescription and the likelihood of an adequate CPAP response (no subsequent therapy change and no discontinuation of therapy) among patients prescribed CPAP.

RESULTS

429/588 (73%) patients with central apneas received an initial trial of CPAP. Younger age, diagnosis by home sleep testing, non-opiate etiology of central apneas, and a lower proportion of central apneas at diagnosis were independently associated with a higher likelihood of an initial CPAP trial. A lower proportion of central apneas was associated with a higher probability of adequate response, while current smoking and opiate-related central apneas predicted an unsuccessful CPAP trial. A new finding was that older age predicted a lower likelihood of an initial CPAP prescription but did not predict an unsatisfactory response to CPAP.

CONCLUSION

Clinicians may incorrectly weigh certain clinical and sleep study characteristics when deciding whether to trial CPAP for patients with central apneas.

Predictors of Initial CPAP Prescription and Subsequent Course with CPAP in Patients with Central Sleep Apneas

Purpose

Guidelines recommend considering an initial trial of continuous positive airway pressure (CPAP) to treat central sleep apnea (CSA). However, practice patterns vary widely. This study investigated predictors for an initial trial of CPAP in patients with central apneas and whether those factors predict adequate treatment response in patients receiving an initial CPAP trial.

Methods

Charts of patients receiving a diagnostic code for CSA following a sleep study during 2016-2018 at a single center were reviewed. Patient factors, initial treatment prescriptions, and subsequent changes to therapy were extracted from electronic health records. Regression models were used to estimate factors associated with an initial CPAP prescription and the likelihood of an adequate CPAP response (no subsequent therapy change or nonadherence) among patients prescribed CPAP.

Results

429/588 (73%) patients with central apneas received an initial trial of CPAP. Younger age, diagnosis by home sleep testing, non-opiate etiology of central apneas, and a lower proportion of central apneas at diagnosis were independently associated with a higher likelihood of an initial CPAP trial. A lower proportion of central apneas was associated with a higher probability of adequate response, while current smoking and opiate-related central apneas predicted an unsuccessful CPAP trial. A new finding was that older age predicted a lower likelihood of an initial CPAP prescription but did not predict a suboptimal response to CPAP.

Conclusion

Clinicians may incorrectly weigh certain clinical and sleep study characteristics when deciding whether to trial CPAP for patients with central apneas.

Severity, comorbidities, and adherence to therapy in Native Hawaiians/Pacific Islanders with obstructive sleep apnea

STUDY OBJECTIVES

Considerable disparities in the prevalence, diagnosis, and management of obstructive sleep apnea (OSA) exist for minority groups in the United States. However, the impact of OSA on Native Hawaiian/Pacific Islanders (NHPIs) has not been evaluated.

METHODS

We performed a retrospective review of patient records of NHPIs who underwent sleep apnea testing between 2014 and 2021 at a single center in Utah to characterize the distribution of comorbidities, disease severity, and treatment adherence.

RESULTS

140 of 141 NHPI patients who underwent sleep testing had OSA. High rates of obesity (94%) and other relevant comorbidities were found. OSA was mostly severe (57%), particularly in males with higher obesity. Adherence to continuous positive airway pressure was low (41% using for 4 or more hours on 70% of nights), and medical factors predicted whether adherence targets were met with modest accuracy (area under the curve 0.699).

CONCLUSIONS

NHPIs at a single sleep center had a high prevalence of comorbidities in association with OSA, a skewed distribution toward severe disease suggestive of barriers to care or unique disease characteristics, and low adherence to continuous positive airway pressure. These findings suggest a high burden of OSA in this population, and further work to characterize barriers to identifying and treating OSA in NHPIs can improve chronic disease outcomes in NHPIs.

CITATION

Locke BW, Sundar DJ, Ryujin D. Severity, comorbidities, and adherence to therapy in Native Hawaiians/Pacific Islanders with obstructive sleep apnea. J Clin Sleep Med. 2023;19(5):967-974.

The association between pulmonary artery enlargement and mortality in an Emergency Department population undergoing computed tomography pulmonary angiography

Findings of an enlarged pulmonary artery diameter (PAd) and increased pulmonary artery to ascending aorta ratio (PA:AA) on contrast-enhanced computed tomography pulmonary angiography (CTPA) are associated with increased mortality in particular groups of patients with cardiopulmonary disease. However, the frequency and prognostic significance of these incidental findings has not been studied in unselected patients evaluated in the Emergency Department (ED). This study aims to determine the prevalence and associated prognosis of enlarged pulmonary artery measurements in an ED cohort. We measured PA and AA diameters on 990 CTPA studies performed in the ED. An enlarged PA diameter was defined as >27 mm in females and >29 mm in males, while an increased PA:AA was defined as >0.9. Poisson regression was performed to calculate prevalence ratios for relevant comorbidities, and multivariable Cox regression was performed to calculate hazard ratios (HR) for mortality of patients with enlarged pulmonary artery measurements. An enlarged PAd was observed in 27.9% of 990 patients and was more commonly observed in older patients and in patients with obesity or heart failure. Conversely, PA:AA was increased in 34.2% of subjects, and was more common in younger patients and those with peripheral vascular disease or obesity. After controlling for age, sex, and comorbidities, both enlarged PAd (HR 1.29, 95% CI 1.00-1.68, p = 0.05) and PA:AA (HR 1.70, 95% CI 1.31-2.22 p < 0.01) were independently associated with mortality. In sum, enlarged PAd and increased PA:AA are common in patients undergoing CTPAs in the ED setting and both are independently associated with mortality.

OSA and Chronic Respiratory Disease: Mechanisms and Epidemiology

Obstructive sleep apnea (OSA) is a highly prevalent disorder that has profound implications on the outcomes of patients with chronic lung disease. The hallmark of OSA is a collapse of the oropharynx resulting in a transient reduction in airflow, large intrathoracic pressure swings, and intermittent hypoxia and hypercapnia. The subsequent cytokine-mediated inflammatory cascade, coupled with tractional lung injury, damages the lungs and may worsen several conditions, including chronic obstructive pulmonary disease, asthma, interstitial lung disease, and pulmonary hypertension. Further complicating this is the sleep fragmentation and deterioration of sleep quality that occurs because of OSA, which can compound the fatigue and physical exhaustion often experienced by patients due to their chronic lung disease. For patients with many pulmonary disorders, the available evidence suggests that the prompt recognition and treatment of sleep-disordered breathing improves their quality of life and may also alter the course of their illness. However, more robust studies are needed to truly understand this relationship and the impacts of confounding comorbidities such as obesity and gastroesophageal reflux disease. Clinicians taking care of patients with chronic pulmonary disease should screen and treat patients for OSA, given the complex bidirectional relationship OSA has with chronic lung disease.

Electronic health record-derived outcomes in obstructive sleep apnea managed with positive airway pressure tracking systems

STUDY OBJECTIVES

To assess the effectiveness of continuous positive airway pressure (CPAP) management guided by CPAP machine downloads in newly diagnosed patients with obstructive sleep apnea (OSA) using electronic health record-derived health care utilization, biometric variables, and laboratory data.

METHODS

Electronic health record data of patients seen at the University of Utah Sleep Program from 2012-2015 were reviewed to identify patients with new diagnosis of OSA in whom CPAP adherence and residual apnea-hypopnea index as measured by a positive airway pressure adherence tracking device data for ≥ 1 year were available. Biometric data, laboratory data, and system-wide charges were compared in the 1 year before and after CPAP therapy. Subgroups were divided by whether patients met tracking criteria, mean nightly usage, and OSA severity.

RESULTS

976 consecutive, newly diagnosed participants with OSA (median age 55 years, 56.6% male) met inclusion criteria. There was a mean decrease of systolic blood pressure (BP) of 1.2 mm Hg and diastolic BP of 1.0 mm Hg within a year of initiation of CPAP therapy. BP improvements in the subgroup meeting CPAP tracking targets were 1.36 mmHg (systolic) and 1.37 mmHg (diastolic). No significant change was noted in body mass index, glycated hemoglobin, or serum creatinine values within a year of starting CPAP therapy, and health care utilization increased (mean acute care visits 0.22 per year to 0.53 per year; mean charges of $3,997 per year to $8,986 per year).

CONCLUSIONS

An improvement in BP was noted within a year of CPAP therapy in newly diagnosed patients with OSA, with no difference in the magnitude of improvement between those meeting tracking system adherence targets.

CITATION

Locke BW, Neill SE, Howe HE, Crotty MC, Kim J, Sundar KM. Electronic health record-derived outcomes in obstructive sleep apnea managed with positive airway pressure tracking systems. J Clin Sleep Med. 2022;18(3):885-894.

Mountain medical kits: epidemiology-based recommendations and analysis of medical supplies carried by mountain climbers in Colorado

OBJECTIVE

: To provide medical kit recommendations for short mountain wilderness recreation trips (hiking, trekking, backpacking, mountaineering etc.) based on the epidemiology of injury and illness sustained and best treatment guidelines. Additionally, to compare these recommendations to the medical kit contents of mountain climbers in Colorado.

METHODS

: A primary literature review concerning the epidemiology of injury and illness in mountain wilderness settings was performed. This information and literature on the efficacy of given treatments were used to derive recommendations for an evidence-based medical kit. The contents of 158 medical kits and the most likely demographics to carry them were compiled from surveys obtained from mountain climbers on 11 of Colorado's 14 000-foot peaks.

RESULTS

: Musculoskeletal trauma, strains, sprains and skin wounds were the most common medical issues reported in the 11 studies, which met inclusion criteria. Adhesive bandages (Band-Aids) were the most common item and non-steroidal anti-inflammatory drugs were the most common medication carried in medical kits in Colorado. More than 100 distinct items were reported overall.

CONCLUSION

: Mountain climbing epidemiology and current clinical guidelines suggest that a basic mountain medical kit should include items for body substance isolation, materials for immobilization, pain medications, wound care supplies, and medications for gastrointestinal upset and flu-like illness. The medical kits of Colorado mountain climbers varied considerable and often lacked essential items such as medical gloves. This suggests a need for increased guidance. Similar methodology could be used to inform medical kits for other outdoor activities, mountain rescue personnel, and travel to areas with limited formal medical care.