Detection of Cerebral Desaturation during Cardiopulmonary Bypass by Cerebral Oximetry

評估腦血氧飽和監視器在體外心肺循環中監測大腦血氧去飽和的情形

陳貞秀(Cheng-Show Chen) ； 呂柏廣(Bor-Kuang Leu) ； 劉康(Kang Liu)

《Acta Anaesthesiologica Sinica》 34卷4期 (1996/12) Pp. 173-178

https://doi.org/10.6955/AAS.199612.0173

摘要

Background: As oxygen consumption increases acutely during rewarming period in extracorporeal cardiopulmonary bypass (CPS), 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 (lNVOS 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. Methods: 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 (SrO_2) and the ipsilateral internal jugular vein was cannulated for measurement of venous oxyhemoglobin saturation (SjO_2) at the jugular bulb. The changes of SjO_2, SrO_2, 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°C in NPT was reached during CPB rewarming. The data obtained were satatistically analyzed for any correlation between two methods using repeated measurements of ANOVA and linear regression. Results: There was no correlation between SjO_2 and SrO_2, between MAP change and SjO_2 or SrO_2 at the start of CPB, but a significant reduction of SjO_2 during rewarming period was observed which was inversely correlative with NPT changes (r^2 = 0.64, p ＜ 0.05). However, SrO_2 did not show a similarity. Conclusions: 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.

關鍵字

cardiopulmonary bypass ； Intraoperative monitoring: cerebral oxygenation ； Monitoring, physiologic: jugular bulb saturation

並列摘要

背景：在體外心肺循環的升溫過程中，大腦氣氣消耗量會急劇增加，此時維持腦部氣氣供需的平衡對預後有絕對之影響。本研究乃藉由腦血氧飽和監視器（INVOS 3100）與內頸靜脈血氧飽和度於體外循環時之相關變化，來評估INVOS 3100在體外心肺循環中，可否有效監測大腦血氧去飽和之狀況。方法：本研究選擇15位接受開心手術的病人，以腦血氧飽和監視器連續監測局部腦血氧飽和度，同時於監視器同側置放內頸靜脈導管，以抽血方式測量頸靜脈血氧飽和度。手術中，分別於施行體外心肺循環之前五分鐘、體外心肺循環開始時、以及每升溫攝氏一度，記錄局部腦血氧飽和度、頸靜脈血氧飽和度、平均動脈壓和溫度的變化。結果：體外心肺循環開始時，平均動脈壓的下降，並不會影響頸靜脈血氧飽和度及局部腦血氧飽和度的改變。在升溫過程，平均動脈壓與腦血氧飽和度亦無明顯變化，但頸靜脈血氧飽和度則明顯降低，且飽和程度與溫度呈反比（r^2 = 0.64, p ＜ 0.05）。結論：研究結果顯示：體外心肺循環過程中，溫度改變的速度是影響大腦血氧平衡最重要的因素，此狀況可由內頸靜脈血氧飽和度之測定獲得証實。此外INVOS 3100監視器敏感度及特異性均差，在體外心肺循環中之監測效果有限，使用價值不高。

並列關鍵字

心肺分流 ； 術中監測：腦血氧定量儀 ； 生理監測：頸靜脈球飽和度