Effects of inspiratory support upon breathing in humans during wakefulness and sleep

摘要: We have compared the effects on breathing of inspiratory mechanical support during wakefulness and sleep in healthy subjects. Nine awake volunteers breathed through a nose mask connected to machine supplying variable levels positive airway pressure (IPAP). Tidal volume (VT), breath duration (TTOT) end-tidal PCO2 (PETCO2) were measured over 1 min steady state periods with IPAP set at minimal level (approx. 2 cmH2O) approx. 10 cmH2O. This protocol was repeated 6 subjects non-REM sleep. When awake, "10 cmH2O IPAP" caused significant increase mean VT from 513 842 ml fall PETCO2 39.7 32.7 mmHg. During sleep, no changes (388 390 ml) or (41.8 39.8 mmHg). In each state, had effect TTOT. Three diaphragmatic surface EMG recorded as an index efferent activity. consistent when but reduction subject conclude that is associated compensatory decrease activity achieve similar tidal maintenance arterial PCO2. "wakefulness drive breathe" may be maintained such results increased despite