Chen C S, Leu B K, Liu K
Department of Anesthesiology, Veterans General Hospital-Kaohsiung, Taiwan, R.O.C.
Acta Anaesthesiol Sin. 1996 Dec;34(4):173-8.
As oxygen consumption increases acutely during rewarming period in extracorporeal cardiopulmonary bypass (CPB), it is crucial to maintain cerebral oxygen delivery at this critical moment. The aim of this study was to evaluate the effectiveness of a cerebral oximeter (INVOS 3100, Somanetics Corporation, Troy, MI, USA) in monitoring cerebral oxygen balance during rewarming in CPB by correlating optical spectroscopic determinations with jugular bulb oxyhemoglobin saturation measurements.
On trial were 15 patients who underwent cardiac surgery under moderate hypothermic nonpulsatile CPB. Infrared spectroscopic soma sensor was placed over the patient's left frontal area to continuously monitor the regional cerebral oxygen saturation (SrO2) and the ipsilateral internal jugular vein was cannulated for measurement of venous oxyhemoglobin saturation (SjO2) at the jugular bulb. The changes of SjO2, SrO2, mean arterial pressure (MAP) and nasopharyngeal temperature (NPT) were recorded 5 min before CPB, instantaneously at initiation of CPB and at the point where every increment of 1 degree C in NPT was reached during CPB rewarming. The data obtained were statistically analyzed for any correlation between two methods using repeated measurements of ANOVA and linear regression.
There was no correlation between SjO2 and SrO2, between MAP change and SjO2 or SrO2 at the start of CPB, but a significant reduction of SjO2 during rewarming period was observed which was inversely correlative with NPT changes (r(2) = 0.64, p < 0.05). However, SrO2 did not show a similarity.
Jugular bulb desaturation which correlated inversely with rewarming speed as disclosed in this study indicated that the temperature change during rewarming was crucial for cerebral oxygen balance. Being less sensitive and still more unspecific, the INVOS 3100 cerebral oximeter is incapable and not recommended for monitoring cerebral oxygen saturation in CPB.
在体外循环（CPB）复温期间，随着氧耗急剧增加，在这个关键时刻维持脑氧输送至关重要。本研究的目的是通过将光学光谱测定结果与颈静脉球部氧合血红蛋白饱和度测量结果相关联，评估脑氧饱和度仪（INVOS 3100，美国密歇根州特洛伊市索曼etics公司）在CPB复温期间监测脑氧平衡的有效性。
对15例在中度低温非搏动性CPB下接受心脏手术的患者进行试验。将红外光谱躯体传感器置于患者左额部区域，以连续监测局部脑氧饱和度（SrO2），并将同侧颈内静脉插管，用于测量颈静脉球部的静脉氧合血红蛋白饱和度（SjO2）。在CPB前5分钟、CPB开始即刻以及CPB复温期间鼻咽温度（NPT）每升高1℃时，记录SjO2、SrO2、平均动脉压（MAP）和鼻咽温度（NPT）的变化。使用重复测量方差分析和线性回归对获得的数据进行统计分析，以确定两种方法之间的相关性。
在CPB开始时，SjO2与SrO2之间、MAP变化与SjO2或SrO2之间均无相关性，但在复温期间观察到SjO明显降低，且与NPT变化呈负相关（r(2)=0.64，p<0.05）。然而，SrO2并未表现出相似性。
本研究表明，颈静脉球部去饱和与复温速度呈负相关，这表明复温期间的温度变化对脑氧平衡至关重要。INVOS 3100脑氧饱和度仪敏感性较低且特异性更差，无法用于监测CPB期间的脑氧饱和度，不推荐使用。
