Comparision Of Impact Of Etomidate And Propofol On Cerebral Oxygen Metabolism In Anesthesia

BackgroundBecause of its smooth and highly controllable process and patients' rapid waking-up postoperatively,intravenous anesthesia have been increasingly used in a variety of clinical surgeries.Recent years,numerous literatures have explored that intravenous anesthesia drugs can improve patients' cerebral function.Propofol have been proved to effectively reduce the extent of cerebral damage and improve cerebral function in both animal experiments and clinical studies,while the role of etomidate on cerebral function is still controversial.The influence of etomidate on cerebral oxygen metabolism in general anesthesia has been studied only confined to craniocerebral surgery and extracorporeal circulation surgery.The present study compares the impact of etomidate and propofol on cerebral oxygen metabolism in general anesthesia of abdominal surgeries,which are the most common surgeries in clinical medicine.ObjectiveTo investigate the role of etomidate and propofol in cerebral oxygen metabolism within anesthesia of abdominal surgeries. MethodThirty-six patients(ASAⅠ～Ⅱ) scheduled for abdominal surgery were studied, which were divided into two groups randomizedly.For the 18 patients in the etomidate group(group E),anesthesia were induced with midazolam,etomidate(0.3 mg/kg), fentanyl and vecuronium bromide,and maintained with etomidate(0.4～0.7 mg/kg·h). For the 18 patients in propofol group(group P),anesthesia were induced with midazolam,propofol(1.5 mg/kg),fentanyl and vecuronium bromide,and maintained with propofol(4-6 mg/kg·h).Fentanyl and vecuronium bromide were injected intravenously intermittently in the operation for muscle relaxation and analgesia. Parameters of hemodynamic,including mean arterial blood pressure(MAP) and heart rate(HR),were recorded at the following four time points:before anesthesia induction (T1),immediately after intubation(T2),30 min after operation(T3),and end of operation(T4).Blood samples of radial artery and internal jugular vein were collected at each time point for blood gas test and lactic acid detection.Hence,the blood oxygen content of radial artery and internal jugular vein(CaO₂ and CjvO₂),as well as the rate of cerebral extraction of oxygen(CEO₂) were calculated.ResultHemodynamic parameters showed that group P had significantly lower MAP than group E at the 3 time points after induction.MAP of group P at T2 and T4 also reduced remarkably compared to that of T1.MAP and HR of group E showed no significant differences between the 4 time points,which suggested a stable hemodynamic status.Neither the arterial nor the venous lactic acid level changed significantly through the operation in group P and E,respectively.The deviation of lactic acid level between arterial and venous blood was very close to 0 and showed no significant changes in the operation for both group P and E.No differences were found in the lactic acid level between the two groups at any of the 4 time points.The oxygen saturation as well as oxygen pressure of both the arterial and venous blood(SaO₂,SjvO₂,PaO₂ and PjvO₂) rose remarkably after anesthesia induction for the two groups,respectively,while the CEO₂ and Da-jvO₂ reduced significantly.No differences were found in SaO₂,SjvO₂,CaO₂,CjvO₂,Da-jvO₂ or CEO₂ between the group P and E at any of the 4 time points.ConclusionEtomidate can lower the cerebral oxygen metabolism rate when used in the induction and maintenance of anesthesia in abdominal operations,with no statistical differences from the effect of propofol.