混合静脉血氧饱和度反映非体外循环冠状动脉旁路移植术中CO变化的准确性

目的 评价混合静脉血氧饱和度(S(-v)O2)反映非体外循环冠状动脉旁路移植(OPCABG)术中CO变化的准确性.方法 择期行OPCABG的病人25例,年龄50～75岁,体重55～85 kg,NYHA心功能分级Ⅰ～Ⅲ级.静脉注射咪达唑仑、芬太尼、哌库溴铵和依托咪酯麻醉诱导,气管插管后行机械通气.麻醉诱导后,右颈内静脉置入漂浮导管,监测S(-v)O2和CI.静脉注射芬太尼和哌库溴铵,静脉输注异丙酚,必要时吸入异氟醚维持麻醉.于切皮前、吻合冠状动脉前降支(LAD)、吻合右冠状动脉(RCA)、吻合左冠状动脉回旋支(LCX)和关胸时,记录S(-v)O2、CI和Hb,计算氧耗指数(VO2I)、氧供指数(DO2I)和氧摄取率(ERO2).于体位改变前即刻、头低位时、搬动心脏时和固定心脏后,记录S(-v)O2和CI.结果 各时点VO2I和Hb比较差异无统计学意义(P＞0.05);S(-v)O2、CI和ERO2于吻合RCA时降低,吻合LCX时降至最低,关胸时恢复至切皮前水平(P＜0.05);DO2I于吻合RCA和吻合LCX时降低,关胸时恢复至切皮前水平(P＜0.05).吻合RCA前和吻合LCX前,与体位变化前比较,头低位/头低右侧位时S(-v)O2升高(P＜0.05);与头低位/头低右侧位时比较,搬动心脏时S(-v)O2降低(P＜0.05);与搬动心脏比较,固定心脏后S(-v)O2升高(P＜0.05);各体位时CI差异无统计学意义(P＞0.05).结论 OPCABG术中病人体位、心脏位置瞬间改变和固定心脏时,S(-v)O2可实时、准确地反映CO的变化.

Accuracy of mixed venous oxygen saturation in reflecting change in cardiac output during off-pump coronary artery bypass grafting

Objective To assess the accuracy of mixed venous oxygen saturation ( S(-v)O2 ) in reflecting the change in CO during off-pump coronary artery bypass grafting (OPCABG) .Methods Twenty-five NYHA Ⅰ -Ⅲ patients of both sexes, aged 50-75 yr, weighing 55-85 kg, undergoing OPCABG, were studied. Anesthesia was induced with midazolam, fentanyl, etomidate and pipecuronium and maintained with propofol infusion and intermittent iv boluses of fentanyl and pipecuronium supplemented with isoflurane if necessary. The patients were mechanically ventilated (VT 8-10 ml/kg, RR 8-10 bpm, I:E 1:2). PETCO2 was maintained at 35-45 mm Hg.Radial artery was cannulated and pulmonary catheter was placed. CI, S(-v)O2 and Hb were monitored and recorded before skin incision, during anastomosis with left anterior descending artery (LAD), right coronary artery (RCA)and left circumflex coronary artery (LCX), when the chest was closed, when the patients' body position was changed and the heart was manipulated. S(-v)O2 and CI were scaled immediately after the pulmonary artery catheter was placed and before anastomosing LAD. Results The CO change in S(-v)O2 was real-time and accurate in reflecting the body positioning and elevation of hearts. There was no simultaneous significant change in CI.Conclusion The CO change in S(-v)O2 is real-time and accurate in reflecting the body positioning and elevation of hearts during OPCABG.