The effect of positive pressure ventilatory patterns on post-bypass lung functions

Area of Science:

• Cardiology
• Pulmonary Medicine
• Anesthesiology

Background:

• Lung function can be affected by cardiopulmonary bypass (CPB).
• Positive ventilatory pressure is a potential method to mitigate these effects.
• This study evaluates different positive pressure ventilation strategies during and after CPB.

Purpose of the Study:

• To evaluate the impact of different positive ventilatory pressure application patterns on lung function.
• To compare manual vital capacity maneuvers (VCM), continuous positive airway pressure (CPAP), and positive end-expiratory pressure (PEEP) in patients undergoing coronary artery revascularization.

Main Methods:

• 30 patients undergoing coronary artery revascularization were randomized into three groups: VCM, CPAP, and PEEP.
• Lung function parameters including PO2, PCO2, alveolar-arterial oxygen difference, shunt fraction, and dynamic lung compliance were measured.
• Intraoperative and postoperative data, including extubation time and ICU stay, were also collected.

Main Results:

• No significant differences in PO2, PCO2, or dynamic lung compliance were observed between the groups.
• Alveolar-arterial oxygen difference was comparable across all groups.
• Intrapulmonary shunt fraction showed significant improvements post-CPB in VCM and PEEP groups, and after chest closure in the CPAP group, though intergroup differences were not significant.

Conclusions:

• All tested positive pressure ventilation methods, applied during or after CPB, effectively maintained ventilatory parameters.
• The findings suggest that various positive pressure ventilation strategies can be employed to support lung function in patients undergoing CPB.