Sandeep Kumar Kar,Tanmoy Ganguly,Chaitali Sen Dasgupta, Anupam Goswami
Introduction: Postoperative pulmonary dysfunctions (PPDs) are fairly common after cardiac surgery with cardiopulmonary bypass (CPB). Prevention of ischemiareperfusion injury is very important to prevent these complications. The authors examined effectiveness of low volume ventilation, no ventilation and continuous positive pressure (CPAP) ventilation during CPB to prevent PPDs.
Methods: 45 patients were enrolled and randomised to three groups. In group NVventilation stopped, in group V- ventilation continued with tidal volume 2 ml/kg, FiO2=50%, respiratory rate 14/ minute, inspiratory expiratory ratio 1:2 and PEEP 5 cm H2O, and in group C- CPAP of 10 cm H2O applied after application of cross clamp. Postoperative arterial blood gas values after induction, onset of CPB, removal of aortic cross clamp and discontinuation of CPB were measured. Inspiratory capacity on first and second postoperative day, extubation time, ICU recovery stay and total hospital stay were taken into consideration.
Results: Baseline patient parameters, type of surgery and CPB and cross clamp times were similar between the groups. PaO2 values were significantly higher in group V after removal of cross clamp. PaCO2 values were similar. Significant improvement of inspiratory capacity found in the low volume ventilation group. ICU recovery stay was lower in the low volume ventilation group. Other parameters did not show any significant result.
Conclusion: Low volume ventilation during CPB is associated with better oxygenation and pulmonary mechanics after cardiac surgery than CPAP or no ventilation. CPAP with 10 cm H2O does not significantly improve postoperative pulmonary function than no ventilation.