ABSTRACT: Background and objective: Upper airway collapsibility predicts the response to several non-continuous positive airway pressure (CPAP) interventions for obstructive sleep apnoea (OSA). Measures of upper airway collapsibility cannot be easily performed in a clinical context; however, a patient's therapeutic CPAP requirement may serve as a surrogate measure of collapsibility. The present work aimed to compare the predictive use of CPAP level with detailed physiological measures of collapsibility. Methods: Therapeutic CPAP levels and gold-standard pharyngeal collapsibility measures (passive pharyngeal critical closing pressure (Pcrit) and ventilation at CPAP level of 0cmH2O (Vpassive)) were retrospectively analysed from a randomized controlled trial (n=20) comparing the combination of oxygen and eszopiclone (treatment) versus placebo/air control. Responders (9/20) to treatment were defined as those who exhibited a 50% reduction in apnoea/hypopnoea index (AHI) plus an AHI<15events/h on-therapy. Results: Responders to treatment had a lower therapeutic CPAP requirement compared with non-responders (6.6 (5.4-8.1) cmH2O vs 8.9 (8.4-10.4)cmH2O, P=0.007), consistent with their reduced collapsibility (lower Pcrit, P=0.017, higher Vpassive P=0.025). Therapeutic CPAP level provided the highest predictive accuracy for differentiating responders from non-responders (area under the curve (AUC)=0.86±0.9, 95% CI: 0.68-1.00, P=0.007). However, both Pcrit (AUC=0.83±0.11, 95% CI: 0.62-1.00, P=0.017) and Vpassive (AUC=0.77±0.12, 95% CI: 0.53-1.00, P=0.44) performed well, and the difference in AUC for these three metrics was not statistically different. A therapeutic CPAP level ≤8cmH2O provided 78% sensitivity and 82% specificity (positive predictive value=78%, negative predictive value=82%) for predicting a response to these therapies. Conclusion: Therapeutic CPAP requirement, as a surrogate measure of pharyngeal collapsibility, predicts the response to non-anatomical therapy (oxygen and eszopiclone) for OSA.
- Continuous positive airway pressure
- Obstructive sleep apnoea
- Personalized medicine
- Upper airway collapsibility