Large variability in definitions of sleep apnea indices used in clinical studies.

STUDY OBJECTIVES: We explored the variability of sleep apnea indices and definitions of obstructive sleep apnea in clinical studies of continuous positive airway pressure. METHODS: In a systematic review of the long-term clinical effects of continuous positive airway pressure, we noted variability across studies in how sleep apnea was defined. We, thus, sought to quantify the heterogeneity. RESULTS: Across 57 comparative studies of long-term clinical outcomes of continuous positive airway pressure, only 40% fully and explicitly reported their definitions of apnea and hypopnea. Most studies defined apnea as 100% airflow cessation, but a minority used 90% or even down to 75% thresholds. Almost half of the studies defined hypopnea as ≥ 50% airflow cessation, but the majority used 30% or even 25% thresholds. Similarly, about half of the studies used a 4% desaturation threshold to define oxygen desaturation and about half used a 3% threshold, with 2 studies using both thresholds for different purposes. Randomized trials were no more consistent or better-reported than observational studies. Studies that cited published criteria generally reported definitions that were different from the cited criteria. CONCLUSIONS: The criteria used to define sleep apnea indices (apnea, hypopnea, and oxygen desaturation) were highly variable, even among studies stating that definitions were based on the same standard criteria. It was often difficult to discern the actual criteria used. The great variability across studies and lack of transparency about their sleep study methods hampers the interpretability and utility of the studies and calls into question whether studies are generalizable from one setting to another. CITATION: Balk EM, Adam GP, D'Ambrosio CM. Large variability in definitions of sleep apnea indices used in clinical studies. J Clin Sleep Med. 2024;20(3):461-468.

Sex Differences in Obstructive Sleep Apnea.

Obstructive sleep apnea (OSA) for many years has been thought to be a disease of men, but research performed more recently has revealed women are at significant risk for OSA as well as the morbidity associated with leaving it untreated. There are estimates that up to 90% of women with severe sleep apnea are not being diagnosed and that if diagnosed, they are less likely to be treated. This article will explore the sex differences in OSA, specifically addressing areas of prevalence, phenotypes, diagnostic criteria, and treatment.

COPD Advanced Patient Management.

COPD is the third leading cause of death in the United States, with current rates of both morbidity and mortality persisting and contributing significantly to long-term disability. More than 11 million Americans are diagnosed with COPD, with an additional 13 million people estimated to be living with undiagnosed disease. For patients diagnosed with COPD, the turning point will be hospitalization. It is important, therefore, that new treatment techniques that manage the signs and symptoms of the COPD and impact the prevalence and severity of exacerbations, hospital admissions, quality of life, and activities of daily living, and innovative clinical management strategies that optimize hospital discharge planning, all show promise in improving outcomes for patients with COPD. In particular, readmissions following COPD hospitalization are associated with high morbidity, mortality, and costs of care, and therefore hospital readmissions are receiving close scrutiny as an opportunity to improve patient care. To this end, programs to assess the presence and severity of dyspnea, and secretion burden and clearance, through implementation of a telemedicine program, use of noninvasive ventilation or supplemental oxygen, and development of a comprehensive self-management program have all been found to be variously effective as elements of a posthospitalization treatment plan. In this series of multi-media presentations and roundtable discussions published in CHEST (available at http://journal.cme.chestnet.org/copd-advanced-patient), leading international faculties discuss some of these specific interventions in detail to provide clinicians with possible solutions to the challenges of managing their patients with advanced COPD.

Restless leg syndrome in pregnancy.

Restless leg syndrome, more recently renamed Willis-Ekbom disease, is a condition that disrupts sleep and occurs more frequently in the pregnant population. We present a 39-year-old woman with restless legs syndrome in the third trimester and discuss the epidemiology, pathophysiology and therapeutic options in the pregnant population while highlighting the challenges posed by the lack of safety data of approved drugs.

Sleep in asthma.

Many patients with asthma experience worsening of symptoms at night. Understanding the mechanism of nocturnal asthma and the factors that exacerbate asthma during sleep would lead to better management of the condition.

Tai Chi Improves Sleep Quality in Healthy Adults and Patients with Chronic Conditions: A Systematic Review and Meta-analysis.

BACKGROUND: Physical activity and exercise appear to improve sleep quality. However, the quantitative effects of Tai Chi on sleep quality in the adult population have rarely been examined. We conducted a systematic review and meta-analysis evaluating the effects of Tai Chi on sleep quality in healthy adults and disease populations. METHODS: Medline, Cochrane Central databases, and review of references were searched through July 31, 2013. English-language studies of all designs evaluating Tai Chi's effect on sleep outcomes in adults were examined. Data were extracted and verified by 2 reviewers. Extracted information included study setting and design, population characteristics, type and duration of interventions, outcomes, risk of bias and main results. Random effect models meta-analysis was used to assess the magnitude of treatment effect when at least 3 trials reported on the same sleep outcomes. RESULTS: Eleven studies (9 randomized and 2 non-randomized trials) totaling 994 subjects published between 2004 and 2012 were identified. All studies except one reported Pittsburg Sleep Quality Index. Nine randomized trials reported that 1.5 to 3 hour each week for a duration of 6 to 24 weeks of Tai Chi significantly improved sleep quality (Effect Size, 0.89; 95% confidence interval [CI], 0.28 to 1.50), in community-dwelling healthy participants and in patients with chronic conditions. Improvement in health outcomes including physical performance, pain reduction, and psychological well-being occurred in the Tai Chi group compared with various controls. LIMITATIONS: Studies were heterogeneous and some trials were lacking in methodological rigor. CONCLUSIONS: Tai Chi significantly improved sleep quality in both healthy adults and patients with chronic health conditions, which suggests that Tai Chi may be considered as an alternative behavioral therapy in the treatment of insomnia. High-quality, well-controlled randomized trials are needed to better inform clinical decisions.

Obstructive sleep apnea in infants.

Obstructive sleep apnea in infants has a distinctive pathophysiology, natural history, and treatment compared with that of older children and adults. Infants have both anatomical and physiological predispositions toward airway obstruction and gas exchange abnormalities; including a superiorly placed larynx, increased chest wall compliance, ventilation-perfusion mismatching, and ventilatory control instability. Congenital abnormalities of the airway, such as laryngomalacia, hemangiomas, pyriform aperture stenosis, choanal atresia, and laryngeal webs, may also have adverse effects on airway patency. Additional exacerbating factors predisposing infants toward airway collapse include neck flexion, airway secretions, gastroesophageal reflux, and sleep deprivation. Obstructive sleep apnea in infants has been associated with failure to thrive, behavioral deficits, and sudden infant death. The proper interpretation of infant polysomnography requires an understanding of normative data related to gestation and postconceptual age for apnea, arousal, and oxygenation. Direct visualization of the upper airway is an important diagnostic modality in infants with obstructive apnea. Treatment options for infant obstructive sleep apnea are predicated on the underlying etiology, including supraglottoplasty for severe laryngomalacia, mandibular distraction for micrognathia, tonsillectomy and/or adenoidectomy, choanal atresia repair, and/or treatment of gastroesophageal reflux.

Pediatric obstructive sleep apnea syndrome.

Obstructive sleep apnea syndrome (OSAS) is a common and serious cause of metabolic, cardiovascular, and neurocognitive morbidity in children. Children with OSAS have increased upper airway resistance during sleep due to a combination of soft tissue hypertrophy, craniofacial dysmorphology, neuromuscular weakness, or obesity. Consequently, children with OSAS encounter a combination of oxidative stress, inflammation, autonomic activation, and disruption of sleep homeostasis. The threshold amount of OSAS associated with adverse consequences varies widely among children, depending on genetic and environmental factors. The choice of therapy is predicated on the etiology, severity, and natural history of the increased upper airway resistance.

Pathophysiology of pediatric obstructive sleep apnea.

Sleep-disordered breathing is a common and serious cause of metabolic, cardiovascular, and neurocognitive morbidity in children. The spectrum of obstructive sleep-disordered breathing ranges from habitual snoring to partial or complete airway obstruction, termed obstructive sleep apnea (OSA). Breathing patterns due to airway narrowing are highly variable, including obstructive cycling, increased respiratory effort, flow limitation, tachypnea, and/or gas exchange abnormalities. As a consequence, sleep homeostasis may be disturbed. Increased upper airway resistance is an essential component of OSA, including any combination of narrowing/retropositioning of the maxilla/mandible and/or adenotonsillar hypertrophy. However, in addition to anatomic factors, the stability of the upper airway is predicated on neuromuscular activation, ventilatory control, and arousal threshold. During sleep, most children with OSA intermittently attain a stable breathing pattern, indicating successful neuromuscular activation. At sleep onset, airway muscle activity is reduced, ventilatory variability increases, and an apneic threshold slightly below eupneic levels is observed in non-REM sleep. Airway collapse is offset by pharyngeal dilator activity in response to hypercapnia and negative lumenal pressure. Ventilatory overshoot results in sudden reduction in airway muscle activation, contributing to obstruction during non-REM sleep. Arousal from sleep exacerbates ventilatory instability and, thus, obstructive cycling. Paroxysmal reductions in pharyngeal dilator activity related to central REM sleep processes likely account for the disproportionate severity of OSA observed during REM sleep. Understanding the pathophysiology of pediatric OSA may permit more precise clinical phenotyping, and therefore improve or target therapies related to anatomy, neuromuscular compensation, ventilatory control, and/or arousal threshold.

Noninvasive ventilation in the older patient who has acute respiratory failure.

Older patients are at significantly increased risk of acute respiratory failure from multiple causes. Noninvasive positive pressure ventilation has been shown to dramatically improve care of patients with acute respiratory failure. Patient selection is important in all patients being treated with noninvasive positive pressure ventilation but is especially important in older patients. Delirium, confusion, and dementia can lead to difficulty for patients in tolerating this procedure and lead to a worsening respiratory status. The presence of a do-not-intubate order does not necessarily preclude the use of noninvasive positive pressure ventilation, and some patients may derive significant benefit from its use. Overall, noninvasive positive pressure ventilation is a reasonable and justifiable option in the treatment of acute respiratory failure in older patients.