Proportional-Assist Ventilation for Minimizing the Duration of Mechanical Ventilation

In critically ill patients, acceleration of liberation from mechanical ventilation is important in order to reduce the risk of complications and to improve long-term outcomes. Whether the use of proportional-assist ventilation with load-adjustable gain factors (PAV+) results in a shorter time to successful liberation from mechanical ventilation than pressure-support ventilation (PSV) is unclear.

In this international clinical trial, we randomly assigned adult patients who had been receiving mechanical ventilation for at least 24 hours and were able to undergo partial ventilatory support with PSV but were not yet ready for liberation from ventilation to undergo PAV+ (which targeted normal work of breathing) or PSV (which targeted a normal respiratory rate and tidal volume). The primary outcome was the time from randomization to successful liberation from mechanical ventilation.

Across 23 centers in seven countries, 722 patients were enrolled, and 573 underwent randomization and were included in the analysis. The median time to successful liberation from mechanical ventilation was 7.3 days (95% confidence interval [CI], 6.2 to 9.7) in the PAV+ group and 6.8 days (95% CI, 5.4 to 8.8) in the PSV group (P = 0.58). The median number of ventilator-free days, the incidence of reintubation and tracheostomy, and the incidence of death by day 90 (29.6% in the PAV+ group and 26.6% in the PSV group), all of which were secondary outcomes, were similar in the two groups. With respect to sedative drugs, the mean (±SD) difference in the midazolam-equivalent dose at day 28 relative to the baseline dose was -1.51±3.28 mg per kilogram of body weight in the PAV+ group and 0.04±0.97 mg per kilogram in the PSV group. Serious adverse events occurred in 31 patients (10.8%) in the PAV+ group and in 28 patients (9.8%) in the PSV group (P = 0.79).

The time to liberation from mechanical ventilation did not differ significantly between the group that underwent PAV+ and the group that underwent PSV. (Funded by the Canadian Institutes of Health Research and others; PROMIZING ClinicalTrials.gov number, NCT02447692.).