Is proportional-assist ventilation with load-adjustable gain factors a user-friendly mode?

Abstract

The aim of this study was to compare the number of interventions (ventilator settings and sedatives, analgesics and vasoactive medication dose manipulations) between critically ill patients on proportional-assist ventilation with load-adjustable gain factors (PAV+) and those on pressure support (PS). Retrospective analysis of data from a previous randomized clinical trial. A total of 208 patients who were mechanically ventilated on controlled modes and met criteria for assisted breathing were randomized to receive either PS (n = 100) or PAV+ (n = 108). Changes in ventilator settings and in the dose of sedatives, analgesics, and vasoactive medications were identified during the period in which the patients were ventilated either with PS (30.4 +/- 17.4 h) or PAV+ (30.0 +/- 18.1 h) and classified as changes to facilitate weaning (CFW) or changes to respond to deterioration (CD). The mean number of changes in ventilator settings was significantly higher with PS than that with PAV+ (10.7 +/- 5.7 vs. 8.9 +/- 4.6). With PS the proportion of these changes classified as CFW was significantly lower than that with PAV+ (59.8% vs. 69.2%). Dyssynchrony as a cause of CD was more likely to occur with PS than with PAV+ (42 vs. 3%). The mean number of changes in the dose of sedatives, analgesics, and vasoactive medications was higher with PS than with PAV+, the difference being significant only for sedatives (4.06 +/- 3.8 vs. 2.82 +/- 3.4). Compared to PS, PAV+ is associated with fewer intervention in terms of ventilator settings and sedative dose changes.