右美托咪定对心脏瓣膜置换术患者体外循环期间局部脑氧饱和度及POCD的影响

Effects of dexmedetomidine on regional cerebral oxygen saturation and POCD during cardiopulmonary bypass in patients undergoing heart valve replacement

目的探讨右美托咪定对心脏瓣膜置换术患者体外循环(cardiopulmonary bypass,CPB)期间局部脑氧饱和度(regional cerebral oxygen saturation,rSO_(2))及术后认知功能障碍(postoperative congnitive dysfunction,POCD)的影响。方法选取80例择期行心脏瓣膜置换术患者,随机分为对照组与观察组,均40例。观察组麻醉诱导前静脉泵注0.5μg/kg右美托咪定,再以0.5μg·kg^(-1)·h^(-1)剂量维持至手术结束,对照组静脉输注生理盐水。两组患者均静脉注射咪达唑仑、舒芬太尼、依托咪酯、罗库溴铵行麻醉诱导,并静脉泵注异丙酚、罗库溴铵,间断输注舒芬太尼维持麻醉。比较两组术前(T)、诱导前(T)、诱导后至CPB开始前(T2)、CPB开始至降温末(T3)、CPB降温末至复温初(T4)、CPB复温初至停机(T5)、停机后30 min(T6)各时间段左侧与右侧rSO_(2)、二氧化碳分压(partial pressure of carbon dioxide,PCO)、血细胞比容(hematocrit,HCT)、血红蛋白(hemoglobin,Hb)、平均动脉压(mean artery pressure,MAP)、肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)、白细胞介素6(interleukin-6,IL-6)水平。分别于术前、术后7 d评估患者的认知功能,并记录POCD发生率。结果两组患者PCO、HCT、Hb、MAP在不同时间点的比较,差异有统计学意义(P<0.05),组间比较及组间与时间点的交互作用差异无统计学意义(P>0.05)。两组患者左侧rSO_(2)、右侧rSO_(2)及血清TNF-α与IL-6的组间比较、不同时间点比较以及组间与时间点的交互作用有统计学意义(P<0.05)。术后两组简易智能量表(mini-mental state examination,MMSE)评分均降低,同时观察组高于对照组(P<0.05)。观察组术后POCD发生率为2.50%,低于对照组17.50%(χ^(2)=5.000,P=0.025)。结论心脏瓣膜置换术中预充右美托咪定并维持给药至术毕,可有效增加患者rSO_(2),降低TNF-α、IL-6水平炎症指标水平,从而有效改善患者CPB期间脑氧供需平衡,并降低POCD发生率。

Objective To investigate the effect of dexmedetomidine on regional cerebral oxygen saturation(rSO_(2))during cardiopulmonary bypass(CPB)and postoperative cognitive dysfunction(POCD)in patients undergoing heart valve replacement.Methods A total of 80 patients undergoing elective heart valve replacement were selected and randomly divided into the control group and the observation group,with 40 cases in each group.In observation group,0.5μg/kg dexmedetomidine was injected intravenously before induction of anesthesia,and then maintained at a dose of 0.5μg·kg^(-1)·h^(-1)until the end of the operation,and the control group was intravenously infused with normal saline.Both groups of patients received intravenous midazolam,sufentanil,etomidate,and rocuronium bromide for induction of anesthesia,and intravenous infusion of propofol and rocuronium bromide,and intermittent infusion of sufentanil to maintain anesthesia.The rSO_(2),partial pressure of carbon dioxide(PCO),hematocrit(HCT),hemoglobin(Hb),mean arterial pressure(MAP),tumor necrosis factor-α(TNF-α),and interleukin-6(IL-6)levels on the left and right sides at each time period of before operation(T),before induction(T1),after induction and before the initiation of CPB(T2),from the initiation of CPB to the end of cooling(T3),and from the end of CPB cooling to the initiation of rewarming(T4),from the initiation of CPB rewarming to shutdown(T5),and at 30 min after shutdown(T6)were compared between two groups.The cognitive function of the patients was assessed before and at 7 d after the operation,and the incidence of POCD was recorded.Results There were significant differences in PCO,HCT,Hb and MAP between two groups at different time points(P<0.05),but there was no significant difference in inter-group comparison and interaction between groups and time points(P>0.05).The difference of interaction between groups,time points and time points between groups were statistically significant with respect to left rSO_(2),right rSO_(2),serum TNF-αand IL-6(P<0.05).The scores of mini-mental state examination(MMSE)in both groups decreased after operation,which were higher in the observation group than in the control group(P<0.05).The postoperative incidence of POCD in the observation group was 2.50%,which was lower than 17.50%in the control group(χ^(2)=5.000,P=0.025).Conclusion Pre-filling dexmedetomidine during heart valve replacement and maintaining the administration until the end of the operation can effectively increase the patient′s rSO_(2),the reduce the levels of TNF-αand IL-6 and the levels of inflammatory indicators.Therefore,it can effectively improve the balance of cerebral oxygen supply and demand during CPB,and reduce the incidence of POCD.