Clinical Trial: Expiratory Flow Limitation and Mechanical Ventilation During Cardiopulmonary Bypass in Cardiac Surgery

Study Status: Not yet recruiting
Recruit Status: Not yet recruiting
Study Type: Interventional



Official Title: Expiratory Flow Limitation and Mechanical Ventilation During Cardiopulmonary Bypass in Cardiac Surgery

Brief Summary:

During general anesthesia a reduction of Functional Residual Capacity (FRC) was observed. The reduction of FRC could imply that respiratory system closing capacity (CC) exceeds the FRC and leads to a phenomenon called expiratory flow limitation (EFL). Positive End-Expiratory Pressure (PEEP) test is a validated method to evaluate the presence of EFL during anesthesia. Aim of the study will be to asses if mechanical ventilation during CardioPulmonary Bypass (CPB) in cardiac surgery could reduce the incidence of EFL in the post-CPB period. Primary end-point will be the incidence of EFL, assessed by a PEEP test, performed at different time-points in operating room. Co-primary end-point will be shunt fraction, determined before and after surgery.

This will be a single center single-blind parallel group randomized controlled trial. Patients will be randomly assigned to three parallel arms with an allocation ratio 1:1:1, to receive one of three mechanical ventilation strategies during CPB.

  1. Ventilation stop during CPB;
  2. Continuous Positive Airway Pressure (CPAP) during CPB, with an airway pressure of 5 cmH2O;
  3. Low tidal low frequency ventilation, with 5 acts per minute, with a tidal volume of 2-3 ml/kg of IBW and a PEEP of 5 cmH2O.