Respiratory function following on-Pump versus off-pump coronary bypass grafting surgery

Objective: Respiratory dysfunction is a very common postoperative complication that occurs after cardiac surgery. Among the suggested causes is cardiopulmonary bypass. We compared the effect of on-pumpcoronary artery bypass grafting (ONCABG) versus off-pumpcoronary arterybypass grafting (OPCABG) on postoperative respiratory function. Methods: Patients were prospectively divided into two groups ONCABG and OPCABG, (n=100 in each). Respiratory variables (Pao2, Paco2, Sao2, and Pao2/Fio2 ratio) were measured prior to induction of anaesthesia then at seven time points (ICU admission, postoperative hours 1, 3, 6, 12, 18, and 24). Time to extubation, rates of reintubation, and use of noninvasive ventilation (NIV) were also evaluated. Results: Baseline preoperative arterial blood gases and alveolar/arterial oxygen pressure gradients were similar in both groups. Postoperatively, all values were significantly higher in the OPCABG group only at ICU admission (p<0.05). No differences were seen in time to extubation, rate of reintubation rate, and use of postoperative NIV. Conclusion: There is a slightly less incidence of lung injury with OPCABG as compared to ONCABG in low-risk patients especially in the early postoperative period.