CPAP titration failure is not equivalent to long-term CPAP treatment failure in patients with obesity hypoventilation syndrome: a case series

Abstract

Study objectives: Medium and long-term trials comparing continuous positive airway pressure (CPAP) with noninvasive ventilation in patients with obesity hypoventilation syndrome have shown no differences in outcomes. However, it remains unclear whether CPAP therapy should be prescribed if significant hypoxemia persists during CPAP titration, despite optimization of upper airway obstructive events or if maximum CPAP pressure is reached. We aimed to examine the effects of 6 weeks of home CPAP therapy on gas exchange in patients with obesity hypoventilation syndrome who failed CPAP titration due to persistent hypoxemia.

Methods: This case series is a substudy of a randomized-controlled trial evaluating efficacy of 3 different PAP modalities in obesity hypoventilation syndrome. Patients randomized to CPAP who failed titration and were prescribed CPAP are included. CPAP failure was defined as spending more than 20% of total sleep time with oxygen saturation below 90% despite adequate resolution of apneas and hypopneas. Follow-up data included in-laboratory polysomnogram on prescribed CPAP after 6 weeks of home CPAP therapy.

Results: Three of seven participants (43%) randomized to CPAP failed CPAP titration. All were morbidly obese, had severe OSA (apnea-hypopnea index > 90 events/h) and severe sleep hypoxemia (percentage of total sleep time with oxygen saturation < 90% [T90] = 60-89%). Hypoxemia (T90: 43-67%, T80: 0-31%, and T70: 0-11%) and hypercapnia (transcutaneous pressure of CO₂ levels > 50 mm Hg) persisted during CPAP titration polysomnogram. The final polysomnogram after 6 weeks of adherent home CPAP therapy showed effective control of obstructive sleep apnea. Hypoventilation and hypoxemia severity decreased significantly in all 3 participants.

Conclusions: Our data suggest that CPAP titration failure does not equal CPAP treatment failure.

Clinical trial registration: Registry: ClinicalTrials.gov; Name: AVAPS-AE Efficacy Study; URL: https://ichgcp.net/clinical-trials-registry/NCT01368614; Identifier: NCT01368614.

Keywords: continuous positive airway pressure failure; hypoxemia; obesity hypoventilation syndrome; obstructive sleep apnea.

© 2020 American Academy of Sleep Medicine.

Figures

Figure 1. Flow diagram outlining screening and participants selection.

AVAPS-AE = average volume assured pressure support with auto expiratory positive airway pressure, BPAP = bilevel positive airway pressure therapy, CPAP = continuous positive airway pressure.

Figure 2. Oxygen saturation at baseline polysomnography, CPAP titration, and CPAP study at the home prescribed pressure after 6 weeks of CPAP use.

Percentage of sleep time with oxygen saturation under 90% (A), under 80% (B) and under 70% (C). Data are reported from total sleep time (TST) on baseline polysomnography, TST at the ideal titrated continuous positive airway pressure (CPAP) pressure on the CPAP titration study, and TST for the polysomnography performed on CPAP, at the home prescribed CPAP pressure, after 6 weeks of home CPAP use.