Comparison of pressure support ventilation and proportional assist ventilation plus for weaning from mechanical ventilation in critically ill patients

Background: Pressure support ventilation (PSV) is a widely used weaning mode that provides varying amount of support with changing lung characteristics. Proportional-assist ventilation plus (PAV+) is a new mode that automatically adjusts to changes in the respiratory system. Aim: This study compared PSV and PAV+ for weaning from mechanical ventilation. Methods: This was a prospective, randomised, control study enrolling 23 adult patients, mechanically ventilated for at least 48 h after passing SBT criteria and a PSV trial of 30 min. They were randomised to receive either PAV+ (Group 1) or PSV (Group 2). A washout time of 30 min was given for patients in either of the group in order to nullify the effect of the previous PSV mode. Two arterial blood gas samples were taken, during the assessment of SBT readiness, and after 60 min on the randomised weaning mode. Clinical signs of respiratory distress and objective weaning criteria were noted. Success and duration of weaning, rapid shallow breathing index (RSBI), rapid shallow breathing index rate (RSBI rate), haemodynamic and respiratory parameters were noted. Results: 13 patients were randomised to PAV+ group; 10 patients to PSV group. Demographic data were similar in both groups. RSBI, RSBI rate, arterial blood gas analysis, peak and mean inspiratory pressure were not different in either group. The average length of ICU stay, duration to wean and days to extubate were almost similar in both groups. Conclusion: Both PAV+ mode and PSV can be used with equal efficiency in patients ready for weaning.