Proportional assist ventilation feasibility in the early stage of respiratory failure: a prospective randomized multicenter trial.

Background: Proportional assist ventilation (PAV+) is an assisted ventilator mode usually applied during weaning. We aimed to determine the feasibility of using PAV+ in the early phase of acute respiratory failure compared to volume-assist control ventilation (V-ACV) in order to shorten the length of mechanical ventilation (MV).

Methods: We conducted a prospective randomized trial comparing high-assistance PAV+ (gain 80%) vs. V-ACV in four university hospital Intensive Care Units. Patients were included based on a previous pilot trial. Length of MV was the main objective. Secondary objectives were length of stay (LOS) in ICU/hospital, and ICU/hospital/60-day mortality. Statistics - Mann-Whitney U Test and Fisher's Exact Test.

Results: We could not find differences in length of MV or any of the analyzed variables between the 52 patients with PAV+ and 50 patients with V-ACV. The high PAV+ failure rate (42%) was attributed to excessive sedation, high respiratory rate, and high respiratory effort.

Conclusions: The use of high-assistance PAV+ in the early phase of MV does not present benefits compared to V-ACV. The high rate of PAV+ failure reinforces the need for sedative optimization, learning curve, and better patient selection.