The Comparison of Pressure (PSV) and Volume Support Ventilation (VSV) as a 'Weaning' Mode

Abstract

Objective: The purpose of our study is to compare two different ventilation modes-pressure support ventilation (PSV) and volume support ventilation (VSV)-as the means of weaning.

Methods: Sixty patients were enrolled in our study. Patients were randomized in to two groups. For the PSV group, FiO2 and airway pressure values were adjusted in order to sustain PaCO2: 35-45 mm Hg, pH>7.32, 6-8 mL kg(-1) TV (tidal volume), and saturation >92%. For the VSV group, FiO2, TV, respiration frequency (f), and peak pressure were adjusted to obtain PaCO2: 35-45 mm Hg, pH>7.32, 6-8 mL kg(-1) TV, saturation >92%, and PO2>60 mm Hg. Every morning, spontaneous breathing was tried in those patients. The patients were extubated after 2 hours of T-piece breathing. The patients who failed spontaneous respiration with the T-piece were returned to mechanical ventilation. Assisted ventilation time (ART), mechanical ventilation time (MRT), total T-piece time (TTT), total weaning time (TWT), and sedation need (SN) values were recorded. "T-test" and "Chi-square" methods were used for statistical analysis.

Results: In our study, the mean ART was 82.60 hours for the PSV group and 56.03 hours for the VSV group (p<0.041). TWT was 93.30 hours for the PSV group and 56.03 hours for the VSV group (p<0.035). The mean TTT was 7.67 hours for the PSV group and 3.83 hours for the VSV group (p<0.007). Nineteen patients in the PSV group and 9 patients in the VSV group required sedation during the weaning process (p<0.01).

Conclusion: In the weaning period, VSV seems to be more advantageous than PSV.

Keywords: Weaning; assisted ventilation modes; ventilatory support.