小剂量右美托咪定在老年患者椎管内麻醉术中的应用

目的 探讨老年人椎管内麻醉中应用小剂量右美托咪定(DEX)镇静的安全性和可行性.方法 30例老年患者,男13例,女17例;年龄65～89岁,平均77岁;随机数字表法分为DEX组和对照组,各15例.椎管内麻醉完成后,DEX组静脉持续输注DEX,剂量为0.4 μg·kg-1·h-1,10 min后持续输注速度改为0.2～0.4 μg·kg-1·h-1,目标以脑电双频谱指数(BIS)值控制在75～85.对照组持续输注等容积生理盐水.记录给药即刻、给药后10、20、30、60 min及术毕时的血压、心率、呼吸频率、脉搏血氧饱和度(SpO2)、呼气末二氧化碳分压(PETCO2)及BIS值,同时记录镇静/警觉(OAA/S)评分及镇静后的其他临床效应,并进行统计学分析.结果 麻醉期间循环、呼吸参数均在正常范围内.给药10 mim后与给药即刻相比,DEX组血压下降10%～15%(P＜0.05),对照组无明显改变.DEX组给药10 min后各时间点BIS值与给药即时相比均显著降低(P＜0.05);DEX组给药30 min后各时间点BIS值均明显低于对照组(95%CI:70～95比80～100;P＜0.05).DEX组给药20 min后各时间点OAA/S评分均低于给药即时,且均明显低于对照组(95%CI：3～4比4～5;P＜0.05).DEX组患者给药后无心动过缓发生;3例术前合并心房颤动病史者,给药后2例转为窦性心律;2例合并严重肺纤维化、哮喘和慢性阻塞性肺疾病者DEX镇静期间呼吸循环功能保持正常;1例合并精神疾病者DEX镇静效果良好.结论 老年患者椎管内麻醉术中应用小剂量DEX镇静有效、可行,其安全性有待大样本研究验证.

Abstract：

Objective To explore the feasibility and safety of sedation with a low dose of dexmedetomidine (DEX) during intrathecal nesthesia in the elderly patients. Methods Thirty elderly patients were randomly divided into the DEX group (n=15) and the control group (n=15). There were 13 males and 17 females with a mean age of 77 years old (range: 65-89 years old). After an induction of intrathecal anesthesia, the patients in the DEX group received an infusion of 0.4 μg·kg-1·h-1 for 10 min. Then the infusion speed was adjusted between 0.2 and 0.4 μg·kg-1·h-1 to maintain the values of bispectral index (BIS) at around 80. An equivalent volume of normal saline was administered in the control group. Blood pressure, heart rate, respiratory rate, pulse oxygen saturation (SpO2), end-tidal carbon dioxide partial pressure (PETCO2) and BIS were recorded at the beginning of DEX infusion, 10, 20, 30 and 60 min after DEX infusion beginning and at the end of surgery. The observer′s assessment of alertness/sedation (OAA/S) scores and the clinical responses were also recorded. A statistical analysis was performed. Results All intraoperative hemodynamic and respiratory parameters were within the normal range in both groups. Compared with the beginning after infusion, blood pressure at the point of 10 min after infusion decreased about 10%-15% (P<0.05) in the DEX group. But there was no such change in the control group. The values of BIS also decreased significantly at each time point after 10 min infusion versus the beginning of administration (P<0.05); as compared with the control group, the values of BIS also decreased significantly at 30, 60 min and the end of infusion (P<0.05). The 95% confidence interval (CI) of BIS values were 70-95 in the DEX group and 80-100 in the control group (P<0.05). In the DEX group, the OAA/S scores were significantly lower at the points of 20, 30, 60 min and the end of infusion versus the beginning after infusion. And it was also lower in the DEX group than that in the control group (95%CI: 3-4 vs 4-5, P<0.05). No bradycardia occurred in the DEX group. Two of three patients with concurrent atrial fibrillation were converted to sinus rhythm after the administration of DEX. Patients with severe lung diseases (pulmonary fibrosis, asthma or chronic obstructive pulmonary disease) maintained normal cardiopulmonary functions in the DEX group. DEX showed a good sedation effect in 1 patient with mental diseases. Conclusion Sedation with a small dose of DEX during intrathecal anesthesia in elderly patients is both feasible and efficacious. But studies of larger sample sizes are warranted to confirm its safety.

Application of sedation with a low dose of dexmedetomidine during intrathecal anesthesia in elderly patients

Objective To explore the feasibility and safety of sedation with a low dose of dexmedetomidine (DEX) during intrathecal nesthesia in the elderly patients. Methods Thirty elderly patients were randomly divided into the DEX group (n=15) and the control group (n=15). There were 13 males and 17 females with a mean age of 77 years old (range: 65-89 years old). After an induction of intrathecal anesthesia, the patients in the DEX group received an infusion of 0.4 μg·kg-1·h-1 for 10 min. Then the infusion speed was adjusted between 0.2 and 0.4 μg·kg-1·h-1 to maintain the values of bispectral index (BIS) at around 80. An equivalent volume of normal saline was administered in the control group. Blood pressure, heart rate, respiratory rate, pulse oxygen saturation (SpO2), end-tidal carbon dioxide partial pressure (PETCO2) and BIS were recorded at the beginning of DEX infusion, 10, 20, 30 and 60 min after DEX infusion beginning and at the end of surgery. The observer′s assessment of alertness/sedation (OAA/S) scores and the clinical responses were also recorded. A statistical analysis was performed. Results All intraoperative hemodynamic and respiratory parameters were within the normal range in both groups. Compared with the beginning after infusion, blood pressure at the point of 10 min after infusion decreased about 10%-15% (P<0.05) in the DEX group. But there was no such change in the control group. The values of BIS also decreased significantly at each time point after 10 min infusion versus the beginning of administration (P<0.05); as compared with the control group, the values of BIS also decreased significantly at 30, 60 min and the end of infusion (P<0.05). The 95% confidence interval (CI) of BIS values were 70-95 in the DEX group and 80-100 in the control group (P<0.05). In the DEX group, the OAA/S scores were significantly lower at the points of 20, 30, 60 min and the end of infusion versus the beginning after infusion. And it was also lower in the DEX group than that in the control group (95%CI: 3-4 vs 4-5, P<0.05). No bradycardia occurred in the DEX group. Two of three patients with concurrent atrial fibrillation were converted to sinus rhythm after the administration of DEX. Patients with severe lung diseases (pulmonary fibrosis, asthma or chronic obstructive pulmonary disease) maintained normal cardiopulmonary functions in the DEX group. DEX showed a good sedation effect in 1 patient with mental diseases. Conclusion Sedation with a small dose of DEX during intrathecal anesthesia in elderly patients is both feasible and efficacious. But studies of larger sample sizes are warranted to confirm its safety.