联合应用脑血流多普勒和近红外光谱测定技术监测深低温停循环选择性脑灌注中大脑功能的意义

摘要

OBJECTIVE To monitor the blood flow velocity and cerebral oxygen saturation changes in the middle cerehral artery ( MCA ) during total aortic arch replacement operation with combined transcranial doppler ( TCD ) and near - infrared spectroscopy ( NIRS ), and to provide clinical basis for protection measures of nervous system. METHODS Twelve adult patients underwent deep hypothermic circulatory arrest ( DHCA ) were applied selective cerebral perfusion during total arch replacement. TCD probe was placed to the temporal windows after induction of anesthesia and the NIRS probe placed on the forehead of patients to collect perioperative, intraoperative and postoperative hemodynamic parameters, cerebral blood flow and cerebral oxygen saturation. RESULTS No patients died relating with the postoperative neurological complications. The mean arterial blood pressure didn t have ohvious correlation with rO2 . The mean velocity of middle cerehral artery ( mVmca ) significantly associated with rO2 . The main pump flow significantly correlated with rO2 . The mVmca, rO2 and SvO2 decreased after antegrade selective cerebral perfusion ( ASCP ) started and recovery after discharge. The ASCP flow was positive correlated with mVmca and rO2. During DHCA, if the ASCP flow was less than 10 ml/kg, the MCA blood flow signal couldnt be detected by TCD; while when it was more than 10 ml/kg, a certain degree of MCA blood flow velocity could be maintained. After cardiopulmonary bypass ( CPB ) , mVmca and rO2 restored to the level before CPB. CONCLUSION Combined using TCD and NIRS can effectively monitor brain function during DHCA with selective cerebral perfusion. It may be an important guide for decreasing brain injury during total aorta arch replacement procedure.%目的 联合应用脑血流多普勒(TCD)和近红外光谱(NIRS)测定技术监测全主动脉弓置换术中的大脑中动脉(MCA)血流流速和脑血氧饱和度的变化,为采取最佳的神经系统保护措施提供临床依据.方法 选取12例拟应用深低温停循环(DHCA)选择性脑灌注行全弓置换术的患者.于麻醉诱导后将TCD探头置于颞窗,将NIRS的探头置于患者的额头,并分别采集围术期、术中以及术后的血流动力学指标、脑血流流速和脑血氧饱和度的指标.结果 全组患者无死亡和术后神经系统并发症.术中平均动脉压与脑血氧饱和度(rO2)没有明显的相关性;而MCA的平均血流速(mVmca)与rO2明显相关;主泵流量与rO2明显相关.开始顺行性脑灌注(ASCP)后,mVmca、rO2和混合静脉血氧饱和度(SVO2)都明显低于ASCP开始前和恢复流量后,且ASCP的流量和mVmca和rO2明显正相关.当DHCA过程中ASCP的流量低于10 ml/kg体重时,TCD则探测不到MCA的血流信号,维持ASCP流量大于10 ml/kg体重可以维持一定的MCA脑血流流速和维持rO2>45%.在体外循环结束后,mVmca和rO2则恢复到体外循环前水平.结论 联合应用TCD和NIRS能有效的反应大脑在DHCA选择性脑灌注期间的血流和氧代谢的状态,对于DHCA选择性脑灌注过程中的大脑灌注流量的调整有重要的指导意义.