Assist-control ventilation vs. low levels of pressure support ventilation on sleep quality in intubated ICU patients

Objective: To compare the impact of assist-control ventilation (ACV) and pressure support ventilation with 6cmH(2)O inspiratory pressure (low PSV) on sleep quality. Design: Prospective randomized cross-over study. Patients: Twenty intubated and mechanically ventilated patients for acute on chronic respiratory failure. Measurements: Patients were monitored by standard polysomnography at the end of their weaning period. Patients were assigned to receive either ACV from 10p.m. to 2a.m. and low PSV from 2a.m. to 6a.m. ACV/low PSV group) or low PSV from 10p.m. to 2a.m. and ACV from 2a.m. to 6a.m. (low PSV/ACV group). Result: There were significant increases in stages 1 and 2 non-rapid eye movement (NREM) sleep and reduction in wakefulness during the first part of the night and significant increases in stages 3 and 4 NREM sleep during the second part of the night were observed with ACV compared to low PSV. A significant negative correlation was observed between the perceived sleep quality and the amount of wakefulness while the amount of stage 2 NREM sleep was positively correlated with perceived sleep quality. Conclutions: ACV was significantly associated with a better sleep quality than those recorded during pressure support. The perception of sleep quality appeared to be better with ACV than with low PSV. On the basis of these results we recommend that intubated and mechanically ventilated patients for acute on chronic respiratory failure should be reventilated at night during their weaning period.