Comparison of the effect of pressure support ventilation and volume assured pressure support ventilation on weaning patients off mechanical ventilation after cardiac surgery

Background: Weaning from mechanical ventilation in the intensive care unit is an important step in the treatment process. More patients in less than 6 hours after cardiac surgery can be separated from mechanical ventilation and extubated. However, 20-40% of patients after cardiac surgery, due to dysfunctional ventilator weaning response (DVWR), still remain under mechanical ventilation. Therefore, a new method of mechanical ventilation such as volume assured pressure support ventilation (VAPSV) is needed in order to reduce the time of weaning from mechanical ventilation. Aim: To compare the effect of pressure support ventilation (PSV) with volume assured pressure support ventilation (VAPS) on time of weaning from mechanical ventilation in patients after cardiac surgery. Methods: This clinical trial study was conducted with the participation of 76 patients undergoing cardiac surgery in Imam Reza hospital of Mashhad, in 2013. Patients were randomly divided into two groups of pressure support ventilation (control) and pressure support ventilation with reliable volume (intervention) groups and the duration of mechanical ventilation and reintubation in both groups was recorded. The data were analyzed by SPSS software version 16 using t-student test and Mann-Whitney tests. Results: The mean duration of mechanical ventilation in VAPS group (65.7±5.8) significantly decreased compared with PSV (87.1± 5.8) (P = 0.015). Conclusion: Results of our study showed that VAPS method could reduce the time of weaning from mechanical ventilation and due to fewer complications; it can be used as an alternative method for weaning off mechanical ventilation.