Objective: Noninvasive ventilation with pressure support (NIV-PS) therapy can augment ventilation; however, such therapy is fixed and may not adapt to varied patient needs. We tested the hypothesis that in patients with chronic respiratory insufficiency, a newer mode of ventilation [averaged volume assured pressure support (AVAPS)] and lateral decubitus position were associated with better sleep efficiency than NIV-PS and supine position. Our secondary aim was to assess the effect of mode of ventilation, body position, and sleep-wakefulness state on minute ventilation (V(E)) in the same patients.
Design: Single-blind, randomized, cross-over, prospective study.
Setting: Academic institution.
Patients and participants: Twenty-eight patients.
Interventions: NIV-PS or AVAPS therapy.
Measurements and results: Three sleep studies were performed in each patient; prescription validation night, AVAPS or NIV-PS, and crossover to alternate mode. Sleep was not different between AVAPS and NIV-PS. Supine body position was associated with worse sleep efficiency than lateral decubitus position (77.9 +/- 22.9 and 85.2 +/- 10.5%; P = 0.04). V(E) was lower during stage 2 NREM and REM sleep than during wakefulness (P < 0.0001); was lower during NIV-PS than AVAPS (P = 0.029); tended to be lower with greater body mass index (P = 0.07), but was not influenced by body position.
Conclusions: In patients with chronic respiratory insufficiency, supine position was associated with worse sleep efficiency than the lateral decubitus position. AVAPS was comparable to NIV-PS therapy with regard to sleep, but statistically greater V(E) during AVAPS than NIV-PS of unclear significance was observed. V(E) was determined by sleep-wakefulness state, body mass index, and mode of therapy.