Hemodynamic changes and oxygen metabolism during off-pump coronary artery bypass grafting / 中华麻醉学杂志

ABSTRACT

Objective To examine the hemodynamic changes and oxygen metabolism during off-pump coronary artery bypass grafting (OPCABG) .Methods Twenty patients (18 male, 2 female) aged (60?8)yr, weighing (71?9)kg undergoing OPCABG were studied. The patients were premedicated with diazepam 10 mg PO 2h before operation and morphine 10 mg and scopolamine 0.3 mg im 30 min before operation. Anesthesia was induced with midazolam 0.1-0.2 mg?kg-1, fentanyl 5-10 ug?kg-1 and vecuronium 0.12-0.15 mg?kg-1 and maintained with 0.5%-2% isoflurane inhalation, fentanyl 10-20 ug?kg-1 and intermittent iv boluses of vecuronium and in some patients propofol infusion. Radial artery was cannulated. Swan-Ganz catheter was placed via internal jugular vein into pulmonary artery. Hemodynamic parameters including MAP, HR, cardiac index (CI), stroke volume (SV), MPAP, PCWP, SVR, left ventricle stroke work index (LVSWI) and RVSWI; oxygen metabolism including oxygen delivery (DO2) , oxygen consumption (VO2) and oxygen extraction ratio (ERO2); regional cerebral oxygen saturation (rSCO2) and arterial blood lactate level (ABL) were measured and recorded before skin incision (A), when pericardium was incised before operation on the heart (B), during operation on the heart (C), 10 min after operation on the heart (D) and at the end of surgery (E) . Results During surgical manipulation on the heart (C) MAP, SV and CI decreased while CVP and HR increased, but the decrease in CI and SV was not significant. During manipulation on the heart(C) DO2 decreased whereas ERO2 increased, but there was no significant change in VO2. After manipulation on the heart (D) DO2 and ERO2 returned to the pre-manipulation level. Arterial blood lactate concentration increased at E. Conclusion OPCABG can be performed uneventfully under our general anesthetic regimen. During operation while the beating heart is being manipulated MAP tends to decrease while CVP and HR increase. The changes are of short duration and do not result in any serious consequeaces.