丙泊酚及七氟烷对单肺通气老年患者脑氧供需平衡的影响

Effects of propofol and sevoflurane on cerebral oxygen metabolism during one-lung ventilation in elderly patients

目的探讨丙泊酚及七氟烷对行肺切除术的老年患者单肺通气(OLV)时脑氧供需平衡的影响。方法将60例择期行肺切除术的老年患者随机分为丙泊酚复合芬太尼全凭静脉麻醉组(P组)和七氟烷复合芬太尼吸入麻醉组(S组),每组各30例。均以脑电双频指数(BIS)40～60为目标,应用丙泊酚或七氟烷完成麻醉。两组患者分别于麻醉诱导前(T_1)、插管后双肺通气(TLV)15 min(T_2)、OLV 30 min(T_3)、恢复双肺通气(rTLV)15 min(T_4)时采集桡动脉及颈静脉球部血行血气分析,并按公式计算肺内分流(Qs/Qt)及脑血流量/脑氧代谢率(CBF/CMRO_2),CBF/CMRO_2>20或<15宝义为脑氧失衡。结果两组患者均顺利完成手术。两组在T_2时间点的血氧饱合度(SjvO_2)均较同组T_1时间点显著升高(P值均<0.05),S组T_2、T_3、T_4时间点的SjvO_2均显著高于P组同时间点(P值均<0.05)。两组均有患者发生脑氧失衡,S组在T_3时间点脑氧失衡的发生率为60%,显著高于P组的30%(P<0.05)。两组在T_3时间点的Qs/Qt均较同组T_2时间点显著增加(P值均<0.05),动脉血氧分压(p_aO_2)均较同组T_2时间点显著下降(P值均<0.05)。结论 OLV期间,BIS为40～60,七氟烷并未显著抑制肺血管收缩反应,与丙泊酚相比对机体氧合无显著影响;丙泊酚对脑氧供需匹配良好,优于七氟烷。

Objective To investigate the effects of propofol and sevoflurane on cerebral oxygen supply and demand equilibrium during one-lung ventilation in elderly patients undergoing thoracic surgery.Methods Sixty elderly patients scheduled for elective thoracic surgery under general anesthesia were randomly divided into propofol group（group P） and sevoflurane group（group S）.During operation the bispectral index（BIS） was maintained at 40-60.Samples of blood gas analysis were collected from the radial artery and jugular bulb at T1 （before induction）,T2（15 min after two lung ventilation[TLV],T3（30 min after one lung ventilation[OLV]）,and T4（15 min after rTLV）.The Qs/Qt and the ratio of cerebral blood flow to cerebral oxygen metabolic rate（CBF/ CMR02） were calculated.Results The operation procedures were successful in both groups.Compared with that at T1,SjvO_2 values at T2 were significantly increased in two groups（all P0.05）.The SjvO_2 values at T2, T3 and T4 were significantly higher in group S than those in group P（all P0.05）.Both groups had abnormal cerebral oxygen metabolism.We found that 60%patients had abnormal cerebral oxygen metabolism in group S at T3i the rate was significantly higher than that in group P（30%,P0.05）.The Q_S/Q_T values at T3 were significantly higher that those at T2 in the two groups（P0.05）,but p_aO_2 values at T3 were significantly lower than those at T2 in the two groups（P0.05）.Conclusions During one-lung ventilation,sevoflurane does not greatly inhibit HPV when BIS being 40-60,and it has a similar effect like propofol on oxygen saturation.Propofol has less influence on cerebral oxygen metabolism than sevoflurane.