Cardiopulmonary Bypass and Continuous Low Tidal Volume

Abstract

Objective: is to compare the effects of low tidal volume ventilation versus no-ventilation in terms of reducing pulmonary dysfunction during cardiopulmonary bypass (CPB) in patients undergoing conventional coronary artery bypass graft (CABG) surgery.

Study Design: Randomized controlled trial study

Place and Duration of Study: This study was conducted at the Dow University of Health Sciences from June 2021 to June 2022.

Materials and Methods: A total of 62 patients who were planned to for cardiac pulmonary bypass graft surgery were enrolled and randomized in two groups. Group A ventilation group was managed with low tidal volume ventilation 3 ml/kg, 12 breaths/min respiratory rate and 5 cmHg PEEP. In group B non-ventilation group ventilation was arrested.

Results: The mean PaO₂/FiO₂ Ratio after intubation of Group A and Group B was 340.91±23.89 and 348.79±24.65, respectively. (p=0.207). The mean PaO₂/FiO₂ Ratio after 1 hour of CPB and PaO₂/FiO₂ Ratio after hours of CPB of Group A was greater than Group B, (p<0.001). Whereas, the A-a oxygen (O₂₎ gradient after 1 hour of cardiopulmonary bypass CPB (kPa) and A-a oxygen (O₂₎ gradient after 4 hour of cardiopulmonary bypass CPB (kPa) of Group A was less than Group B, (p<0.001). The mean ventilation time of Group A and Group B was 5.61±0.86 hours and 7.77±0.98 hours, respectively. (p<0.001). While, ICU stay and hospital stay of both the groups was almost same, (P>0.050).

Conclusion: In cardiac surgery patients especially cardiopulmonary bypass low tidal volume ventilation is associated with reduce risk of complications and better oxygenation during cardiopulmonary bypass.