The changes of hemodynamics and oxygen metabolism in patients undergoing off-pump coronary artery bypass grafting

Objective To observe the changes of hemodynamics and oxygen metabolism in patients undergoing off-pump coronary artery bypass grafting (OPCABG), and analyzed its characteristics in anesthetic management. Methods From January 2002 to December 2006,87 cases with coronary heart disease underwent off-pump coronary artery bypass grafting (OPCABG)in selective period. The fentanyl, isoflurane, N2O and propofol were used to perform inhalation combined with intravenous anesthesia in all cases. Hemodynamics were determined by Swan-Granz catheter and continuous cardiac output method. The every time point and hemodynamic parameters were detected as follows: before operation (T1), after sternotomy (T2), before the beginning of graft anastomoses (T3), during anterior descending artery grafting (T4), during right coronary artery or posterior descending artery grafting(T5), during left circumflex or diagonal branch artery grafting(T6), after finished vascular anastomoses. and the heart returned to normal position (T7), before the chest closure(T8), and at the end operation (T9). Aterial and mixed venous blood samples were taken to do blood gas analysis,and DO2I, VO2I and ERO2 were calculated at the T1, T2,T3,1.5 h after the beginning of graft anastomoses (T4-8) and T9. postoperative removing tracheal catheter time and satying ICU time were recorded. Results HR, CO, CI, PAWP, MPAP, LVWI, RVWI, RVSWI, DO2I, SO2 and PO2 were increased significantly while VO2I and ERO2 were decreased significantly at T2 and T3 compared with that at T1 (P0.05 or 0.01), but there were no significant changes in SI, LVSWI and PVRI (P 0.05). During graft anastomoses (T4?T5?T6), CI, SI, MAP, LVWI, LVSWI, RVWI, RVSWI, DO2I, SO2, PO2 and VO2I were decreased in different degree, but HR, RAP, MPAP, PAWP and ERO2 were increased significantly (P0.05 or 0.01). From T7 to T9, the parameters above were restored gradually to T1 level or were improved obviouly. The average postoperative removing times of tracheal catheter and staying ICU time were 6.5±2.3h and 2.6±1.4 d. Conclusion Under reliable hemodynamic monitoring and reasonable use of vasoactive agents, OPCABG can be performed uneventfully during graft anastomoses.