AVAPS-AE versus ST mode: A randomized controlled trial in patients with obesity hypoventilation syndrome

Abstract

Background and objective: Average volume-assured pressure support-automated expiratory positive airway pressure (AVAPS-AE) combines an automated positive expiratory pressure to maintain upper airway patency to an automated pressure support with a targeted tidal volume. The aim of this study was to compare the effects of 2-month AVAPS-AE ventilation versus pressure support (ST) ventilation on objective sleep quality in stable patients with OHS. Secondary outcomes included arterial blood gases, health-related quality of life, daytime sleepiness, subjective sleep quality and compliance to NIV.

Methods: This is a prospective multicentric randomized controlled trial. Consecutive OHS patients included had daytime P_a CO₂ > 6 kPa, BMI ≥ 30 kg/m² , clinical stability for more than 2 weeks and were naive from home NIV. PSG were analysed centrally by two independent experts. Primary endpoint was sleep quality improvement at 2 months.

Results: Among 69 trial patients, 60 patients had successful NIV setup. Baseline and follow-up PSG were available for 26 patients randomized in the ST group and 30 in the AVAPS-AE group. At baseline, P_a CO₂ was 6.94 ± 0.71 kPa in the ST group and 6.61 ± 0.71 in the AVAPS-AE group (P = 0.032). No significant between-group difference was observed for objective sleep quality indices. Improvement in P_a CO₂ was similar between groups with a mean reduction of -0.87 kPa (95% CI: -1.12 to -0.46) in the ST group versus -0.87 kPa (95% CI: -1.14 to -0.50) in the AVAPS-AE group (P = 0.984). Mean NIV use was 6.2 h per night in both groups (P = 0.93). NIV setup duration was shorter in the AVAPS-AE group (P = 0.012).

Conclusion: AVAPS-AE and ST ventilation for 2 months had similar impact on sleep quality and gas exchange.

Keywords: chronic respiratory failure; non-invasive ventilation; obesity hypoventilation syndrome; polysomnography; sleep apnoea.