Abstract: Objective · To find out the optimal positive end expiratory pressure (PEEP)electrical impedance tomography (EIT) for better lung recruitment and ventilation distribution in patients undergoing off pump coronary artery bypass grafting surgery (OPCAB). Methods · 105 patients under went OPCAB Jan. 2017 to Dec. 2017 were analysed. Patients were randomly divided into two groups, i.e. experiment group (54 cases) and control group (51 cases). Four regions of interest (ROI) were recordedEIT. PEEP were 3 cmH2O in control group while PEEP were increased stepwiseby 2 cmH2O 0 cmH2O to 14 cmH2O in experiment group. The optimal PEEP for lung recruitment was applied in experiment group. Postoperative oxygenation index (PaO2/FiO2) and pulmonary complication were compared between two groups. Results · The overall mortality was 2 (1.90%). The incidence of postoperative pulmonary complication, pulmonary infection, atelectasis, pleural effusion were 18.10%, 2.86%, 18.10%, 18.10%, respectively. The optimal PEEP zone was 6-9 cmH2O. PaO2/FiO2 was significantly increased with the optimal PEEP in experiment group (P0.00). There were significant differences in postoperative pulmonary complication between two groups (P0.02). Conclusion · EIT can directly monitor ventilation distribution and titrate suiPEEP for better lung recruitment in patients undergoing OPCAB. It can significantly reduce postoperative pulmonary complication, improve oxygenation, and decrease ICU stay and ventilation duration.

Key words: electrical impedance tomography (EIT), off pump coronary artery bypass grafting surgery (OPCAB), lung recruitment, positive end expiratory pressure (PEEP)