坐位神经外科手术期间血流动力学及氧代谢变化

Effects of sitting position and general anesthesia on systemic hemodynamics and oxygen metabolism

目的 观测神经外科手术中坐位全身麻醉对体循环血流动力学及全身氧代射的影响。方法 2 8例后颅窝及后颈髓手术病人 ,采用静脉复合诱导、吸入七氟醚或安氟醚及伍用芬太尼维持麻醉 ,以Swan Ganz导管、动脉和混合静脉血气监测及Fick方法测定血流动力学和氧代谢参数 ,包括CI、RAP、PCWP、SVRI、pHa、PaCO2 、PvCO2 、PaO2 、SvO2 、Hct、T、DO2 、及VO2 等。分别在麻醉前、坐位前、坐位后、坐位 6 0分钟、坐位 12 0分钟及术毕平卧位等时间点进行测定。结果 麻醉诱导后及坐位手术期间CI一直呈降低并维持在正常值的低限 (P <0 0 0 1) ,RAP略增加 ,MAP略下降 ,而SVRI呈持续增高 (P <0 0 0 1)。此期间DO2 和VO2 显著减少 (P <0 0 5～ 0 0 0 1) ,但PaCO2 、PvCO2 、pHa、及HCO-3 等参数均未见明显改变。术毕平卧后虽然CI、SVRI、T、Hct、DO2 、VO2 及PaCO2 等恢复或维持至麻醉前水平 ,但pHa和BE B呈有意义的下降、PvCO2 呈有意义的增高 (P <0 0 5 )。结论 神经外科病人在坐位全麻手术期间只要维持血流动力学平稳 ,机体全身氧代谢可得到维持 ,但在麻醉苏醒期有易发生氧代谢异常的倾向。

Objective To study the effects of sitting position on systemic hemodynamics and oxygen metabolism during anesthesia and neurosurgery.Methods 28 patients scheduled for posterior fossa and posterior cervical spinal surgery were anesthetized with sevoflurane fentanyl pancuronium or enflurane fentanyl pancuronium.Swan Ganz catheter technique and arterial and mixture venous blood gas analysis were used to obtain hemodynamics and blood gas data and Fick equation were used to calculate DO 2 and VO 2.The detection time points were as follows:before anesthesia induction,before sitting position, after sitting position,at sitting 60min,sitting 120min and at the supine position after completion of surgery.Results After induction of anesthesia and during operation in sitting position,CI decreased under the preanesthesia value ( P< 0 001) with RAP increasing and MAP decreasing slightly,and SVRI raising persistently.DO 2 and VO 2 were significanly decreased ( P< 0 05～0 001),but no marked changes in PaCO 2,PvCO 2,pHa and HCO - 3 were found during the period.At the supine position after surgery,CI,SVRI,T,Hct,DO 2,VO 2 and PaCO 2 were returned or maintained at the preanesthesia values.However,pHa,pHv and BEb decreased and PvCO 2 increased significantly ( P< 0 05).Conclusion During neurosurgical procedure under general anesthesia with sitting position,global oxygen delivery and consumption can be kept well as long as the hemodynamics are properly maintained.Tissue oxygenation and metabolism may tend to imbalance during the postanesthetic recovery period.