The changes in cerebral metabolism and depth of anesthesia during hypothermic cardiopulmonary bypass
- VernacularTitle:低温体外循环中心脏瓣膜置换术患者脑代谢与麻醉深度的变化
- Author:
Bin CHEN
;
Bin LIU
;
Guo CHEN
- Publication Type:Journal Article
- Keywords:
Cardiopulmonary bypass;
Hypothemia, induced;
Brain;
Electroencephalography;
Evoked potentials, auditory
- From:
Chinese Journal of Anesthesiology
1996;0(09):-
- CountryChina
- Language:Chinese
-
Abstract:
Objective To evaluate the effects of hypothermic cardiopulmouary bypass(CPB) on depth of anesthesia measured by BIS and auditory evoked potential index(AEPI) monitoring and cerebral O_2 and glucose metabolism. Methods Twenty-eight ASA Ⅱ-Ⅲ patients of both sexes(15 males, 13 females) aged 29-55 yrs undergoing elective cardiac valve replacement under hypothemic CPB were studied. Patients were excluded from the study if they had hearing disturbance, hepato-renal dysfunction, diabetes melhtus, hypertension, cerehro-vascular or mental diseases. The patients were premedicated with intramuscular morphine 0.15 mg?kg~(-1) and scopolamine 0.3mg. Anesthesia was induced with midazulam 0.05-0.1 mg?kg~(-1), fentanyl 10 ug?kg~(-1) and pancuronium 0.1 mg?kg~(-1) and maintained with intermittent ⅰ.ⅴ. boluses of fentanyl, diazepam and pancuronium. Radial artery was cannulated for BP monitoring and blood sampling. A CVP catheter was inserted into right internal jugular vein and advanced in a cephalad direction until jugular bulb for blood sampling. BP, HR, T℃(naso-pharyngeal), BIS and AEPI were continuously monitored during operation. Arterial and jugular bulb blood samples were obtained before CPB(T_1), T℃ was lowered to 33℃(T_2)during stable hypothermia(T_3) during rewarming at 33℃(T_4) and 30 min after termination of CPB(T_5) for blood gas analysis and determination of glucose and lactate concentrations. Cerebral oxygen extraction rate(O_2 ER) cerebral glucose extraction rate(GER), arterial-jugular bulb venous lactate difference(DLa-jv) and arterial-jugular bulb venous O_2 content difference (Ca-jvO_2) were calculated. Results Blood glucose and lactate concentrations were significantly increased, while arterial blood pH and DLa-jv did not change significantly during CPB. Cerebral oxygen extraction rate(O_2ER), cerebral glucose extraction rate(GER) and arterial-jugular bulb venous O_2 content difference (Ca-jvO_2) decreased while jugular bulb venous oxygen saturation (SjvO_2) increased with decreasing body temperature. BIS and AEPI values decreased with decreasing T℃ and both were well correlated with T℃. AEPI was positively correlated with O_2 ER and negatively correlated with Ca-jvO_2 whereas BIS was positively correlated with PaO_2. Conclusion Cerebral metabolism is decreased during hypothermic CPB which also deepens anesthetic depth measured by BIS and AEPI monitoring.
