Adaptive servo-ventilation and deadspace: effects on central sleep apnoea
Central Sleep Apnoea (CSA) occurs commonly in heart failure. Adaptive servo-ventilation (ASV) and deadspace (DS) have been shown in research settings to reverse CSA. The likely mechanism for this is the increase of PaCO2 above the apnoeic threshold. However the role of increasing FiCO2 on arousability remains unclear. To compare the effects of ASV and DS on sleep and breathing, in particular effects on Arousal Index (ArI), ten male patients with heart failure and CSA were studied during three nights with polysomnography plus measurements of PetCO2. The order of the interventions control (C), ASV and DS was randomized. ASV and DS caused similar reductions in apnoea–hypopnoea index [(C) 30.0 ± 6.6, (ASV) 14.0 ± 3.8, (DS) 15.9 ± 4.7 e h−1; both P < 0.05]. However, DS was associated with decreased total sleep time compared with C (P < 0.02) and increased spontaneous ArI compared to C and ASV (both P < 0.01). Only DS was associated with increased ΔPetCO2 from resting wakefulness to eupnic sleep [(C) 2.1 ± 0.9, (ASV) 1.3 ± 1.0, (DS) 5.6 ± 0.5 mmHg; P = 0.01]. ASV and DS both stabilized ventilation however DS application also increased sleep fragmentation with negative impacts on sleep architecture. We speculate that this effect is likely to be mediated by increased PetCO2 and respiratory effort associated with DS application.
Document Type: Research Article
Affiliations: Academic Unit of Sleep and Breathing
Publication date: June 1, 2006