目标导向液体治疗对老年颅脑手术患者术后脑代谢和脑保护的作用机制研究

Effects of goal directed fluid therapy on brain metabolism and brain protection in elderly patients undergoing craniocerebral surgery

目的 探讨目标导向液体治疗对老年颅脑手术患者术后脑代谢和脑保护的作用机制.方法 选取2015年1月—2016年12月在河北省唐山市开平医院接受颅脑手术的80例老年患者的临床资料进行回顾性分析,其中接受目标导向液体治疗40例（观察组）,常规输液治疗40例（对照组）.比较两组患者在麻醉诱导前（T1）、气管插管即刻（T2）、切开硬脑膜即刻（T3）、切开硬脑膜后1 h（T4）以及手术结束时（T5）的心率（HR）、平均动脉压（MAP）、心输出量指数（CI）水平以及脑代谢、血乳酸各项指标水平变化情况.结果 观察组患者尿量、输液总量、胶体量分别为（1602.7±305.3）mL、（3215.8±442.8）mL、（2028.1±345.2）mL,均高于对照组的（1105.5±256.2）mL、（2604.3±352.6）mL、（855.6±278.6）mL;而晶体量为（1142.5±242.5）mL,则低于对照组的（2102.7±102.8）mL,差异均有统计学意义（P值均〈0.05）.与T1时相比,两组T2、T3、T4、T5时的HR水平均有所下降;MAP水平在T2时下降明显,而在T4、T5时明显升高;CI水平在T4、T5时明显升高,差异均有统计学意义（P值均〈0.05）.T4、T5时观察组MAP及CI水平高于对照组,差异均有统计学意义（P值均〈0.05）.与T1时相比,两组患者动脉血氧含量（CaO2）、静脉血氧含量（CjvO2）水平均下降,且在T2、T3、T4、T5时观察组患者CaO2水平均高于对照组,而CjvO2水平均低于对照组,差异均有统计学意义（P值均〈0.05）.与T1时相比,两组T3、T4、T5时的动脉乳酸值（aLac）水平均明显上升,且观察组水平均明显低于对照组;与T1时相比,两组T3、T4、T5时的静脉乳酸值（vLac）水平均明显上升,且观察组T2、T3、T4、T5时vL-ac的水平均明显低于对照组;与T1时相比,两组T2～T5时的脑乳酸生成率（LacPR）水平均降低;差异均有统计学意义（P值均〈0.05）.结论 目标导向液体治疗可有效改善老年颅脑手术患者心脏前负荷,同时改善脑代谢,其主要作用机制可能与降低脑乳酸生成有关.

Objective To investigate the mechanism of goal directed fluid therapy on brain metabolism and brain protection in elderly patients undergoing craniocerebral surgery. Methods The clinical data of 80 elderly patients undergoing craniocerebral surgery in Kaiping Hospital of Tangshan from January 2015 to December 2016 were retrospectively analyzed. Among them, 40 patients （ observation group） received goal directed fluid therapy, and another 40 patients （ control group ） received routine surgery. The heart rate （ HR） , mean arterial pressure （ MAP） and cardiac output index （ CI） levels as well as changes in brain metabolism and blood lactate levels were detected before induction of anaesthesia （ T1 ） , tracheal intubation immediately （ T2 ） , incision of dural immediately （ T3 ） , incision of dura after 1 h （ T4 ） and the end of surgery （ T5 ） between the two groups. Results The urine volume, total infusion volume, and colloidal volume were （1602. 7 ± 305. 3） mL, （3215. 8 ± 442. 8） mL, and （2028. 1 ± 345. 2） mL in the observation group, respectively, which were significantly higher than those in the control group [（1105. 5 ± 256. 2） mL, （2604. 3 ± 352. 6） mL, （855. 6 ± 278. 6） mL],but the amount of crystals was （1142. 5 ± 242. 5） mL, which was significantly lower than that of the control group [（2102. 7 ±102. 8） mL], with statistical differences between the two groups （all P values〈0. 05）. Compared with the time point of T1 , the HR levels in the two groups at T2 , T3 , T4 and T5 were significantly decreased, and the MAP level was significantly decreased at T2 , but increased at T4 and T5 , and the CI level was significantly elevated at T4 and T5 . At the time-point of T4 and T5 , the MAP and CI levels in the observation group were significantly higher than those in the control group, and there was a statistically significant difference between the two groups （all P values〈0. 05）. Compared with time-point of T1, the levels of CaO2 and CjvO2 were both decreased significantly in the two groups, and the CaO2 levels in the observation group were significantly higher than those in the control group at T2 , T3 , T4 and T5 , but the CjvO2 level was significantly lower than that of the control group, with statistically significant difference between the two groups （ all P values 〈0.05）. Compared with time point of T1, the arterial lactate （aLac） levels in the two groups increased significantly from T3 , T4 and T5 , and the observation group was significantly lower than the control group, and meanwhile, the aLac levels were significantly increased in the two groups from T3 , T4 and T5 , and the vein lactate（ vLac） levels in the observation group from T2 , T3 , T4 and T5 were significantly lower than those in the control group. However, when compared with time-point of T1 , the brain lactate production rate （ LacPR） levels in the two groups from T2 , T3 , T4 and T5 were significantly decreased, and there was a statistically significant difference between the two groups （all P values 〈 0. 05）. Conclusions Goal directed fluid therapy can effectively improve the cardiac preload and brain metabolism in the elderly patients undergoing craniocerebral surgery, and the main mechanism may be related to the reduction of lactate production in brain.