Health Conditions and Service Use Among Intimate Partner Violence Shelter Residents.

Obstructive sleep apnea (OSA) is a common sleep-related breathing disorder characterized by recurrent upper-airway obstruction, intermittent hypoxemia, and sleep fragmentation. Global estimates suggest that over nine hundred million adults are affected, highlighting its substantial public health impact. Positive airway pressure (PAP) remains the first-line therapy and significantly improves daytime functioning, cardiovascular outcomes, and quality of life when appropriately titrated. Optimal positive airway pressure is generally established via manual or auto-titration, with auto-titrating positive airway pressure (APAP) recommended only for selected adults with uncomplicated OSA and without significant cardiopulmonary or sleep comorbidities. Beyond restrictions for specific individuals, the suitability of pressure obtained through auto-titration also depends on the accuracy of the machine’s inherent algorithm. Bench evaluations indicate that commercially available APAP systems differ markedly in their responsiveness to obstructive respiratory events and in pressure modulation, reflecting inherent algorithmic heterogeneity. Additionally, transitioning patients stably adapted to APAP to fixed CPAP preserves therapeutic efficacy while reducing costs, underscoring that APAP’s long-term clinical advantages are not unequivocally established. Therefore, whether there exists a more convenient method for obtaining CPAP pressure values has been a longstanding concern. Yet determining the optimal therapeutic pressure requires in-laboratory titration, a process that is resource-intensive, time-consuming, and often limited by laboratory capacity, contributing to delays in treatment initiation. To improve accessibility, multiple studies have attempted to predict CPAP pressure using demographic and conventional polysomnographic (PSG) respiratory measures—such as the apnea–hypopnea index (AHI), oxygen desaturation index (ODI), and minimum oxygen saturation (SpO₂-Min). However, a study validated the currently published prediction formulas and found that most of existing prediction formulas often exhibit weak explanatory power. This limitation may reflect a fundamental mismatch between what event-based metrics quantify and what actually determines CPAP requirements. Current evidence indicates that the pathophysiology of obstructive sleep apnea can be conceptualized within the PALM framework, in which pharyngeal airway collapsibility (P), arousal threshold (A), ventilatory control instability or loop gain (L), and upper-airway muscle responsiveness (M) jointly determine disease expression and treatment response. A major methodological advance in this field has come from the work of Scott A. Sands and colleagues, who demonstrated that these traits can be quantified noninvasively from routine PSG using airflow-derived ventilatory patterns and associated oxygenation and arousal signals. Despite these advances, the clinical application of endotype-derived metrics for predicting fixed CPAP titration pressure among the group of patients diagnosed with OSA remains limited.