不同麻醉药物对老年骨科手术患者术后认知功能的影响及其机制

目的：比较异氟烷、七氟烷两种吸入性麻醉药对老年骨科手术患者术后认知功能障碍（POCD）及血清S-100β蛋白、炎性因子表达水平的影响，分析探讨其与神经炎症的关系。方法：选择择期进行骨科手术的老年患者90例（其中行髋关节置换术患者42例，行骨折内固定术患者48例），随机分为A、B两组，每组45例，全身诱导麻醉后分别以异氟烷、七氟烷维持麻醉。手术麻醉期间记录两组患者的手术时间、麻醉时间和苏醒时间；分别于手术麻醉前（T₀）和手术后6 h（T₁），1 d（T₂），3 d（T₃），5 d（T₄）抽取两组患者外周静脉血，并采用MMSE评分法进行神经精神功能测试，计算POCD发生率；ELISA法检测血清中S-100β及炎性因子IL-1β、TNF-α、IL-6的浓度。结果：（1）两组手术时间、麻醉时间无明显差异（P>0.05），A组术后苏醒时间明显长于B组（P<0.05）。（2）术前两组的MMSE评分、血清指标水平均无显著差异（P>0.05）；A组术后1 d和3 d时MMSE评分明显低于同组术前及B组对应时间点（P<0.05），且术后5 d内POCD发生率明显高于B组（P<0.05）。（3）A组术后1 d和3 d时，血清S-100β、IL-1β及IL-6水平均明显高于同组术前及B组对应时间点（P<0.05）；两组术后6 h，1 d，3 d时TNF-α水平均显著高于术前（P<0.05），且A组比B组升高程度更大（P<0.05）。结论：吸入性麻醉药异氟烷可引起老年患者POCD以及中枢神经特异蛋白S-100β、炎性因子表达增加，而七氟烷的影响不明显，其机制可能与老年患者中枢神经系统炎症有关。

Effect and mechanism of different anesthetics on postoperative cognitive functions in elderly patients after orthopedic surgery

OBJECTIVE To compare the changes of postoperative cognitive function in elderly patients after orthopedic surgery between isoflurane and sevoflurane anesthesia, respectively, and explore the mechanism of postoperative cognitive dysfunction (POCD).METHODS Ninety elderly patients undergoing orthopedic surgery (42 with replacement of hip joint and 48 with fracture fixation) under general anesthesia were randomly divided into group A and group B, who respectively inhaled isoflurane and sevoflurane to maintain anesthesia. Operation time, anesthesia time and waking time were recorded. Peripheral venous blood of all patients were collected before and at the 6 h (T₁), 1 (T₂), 3 (T₃), 5 (T₄) days after the operation to detected the concentrations of S-100β, IL-1β, TNF-α and IL-6. The mini mental state examination (MMSE) was used to assess the postoperative cognitive function before and at the 6 h, 1, 3_, and 5 days after the operation, and the incidence rate of POCD was calculated.RESULTS No significant difference was found in operation time or anesthesia duration between two groups (P>0.05). The recovery time in group A was obviously longer than that in group B (P<0.05). In preoperative period, no significant difference was found in MMSE score or levels of serum indexes between two groups (P>0.05). The MMSE score in group A at 1, 3 days after operation were significantly lower than that before operation and those in group B (P<0.05), and the incidence rate of POCD was significantly higher than that in group B (P<0.05). The levels of serum S-100β, IL-1β and IL-6 in group A at 1, 3 days after operation were all significantly higher than that before operation and those in group B (P<0.05). The TNF-α level in both groups at 6 h, 1, 3 days after the operation were greatly higher than that before operation, particularly in group A (P<0.05).CONCLUSION The isoflurane anesthesia can result in POCD and increased levels of S-100β, IL-1β, TNF-α and IL-6, while but sevoflurane will not. The mechanism of POCD may closely relate to the central nervous system (CNS) inflammation.