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

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.