Department of Surgery and Anaesthesiology Centre, PLA General Hospital, Beijing, China.
Acta Anaesthesiol Scand. 2018 Jul;62(6):848-856. doi: 10.1111/aas.13087. Epub 2018 Feb 9.
The median effective dose (ED ) of sedative dexmedetomidine adjuvant to peripheral nerve block (PNB) has not yet been verified in elderly patients. This study assessed the ED of intravenous dexmedetomidine for sedation in elderly patients who were undergoing total knee arthroplasty (TKA) with PNB.
Forty-two patients aged 65-85 years were included and stratified into two groups according to age: young-old group (aged 65-74 years) and middle-old group (aged 75-85 years). After the PNB was performed, a pre-calculated dose of dexmedetomidine was administered for 10 min. The Observer's Assessment of Alertness/Sedation scale, bispectral index score, blood pressure and heart rate were recorded. ED values of dexmedetomidine for adequate sedation were estimated by the up-and-down method of Dixon and probit regression.
The ED of single-dose dexmedetomidine adjuvant to PNB was 0.57 μg/kg (95% confidence interval [CI], 0.47-0.65) in the young-old group and 0.38 μg/kg (95% CI, 0.28-0.46) in the middle-old group. The ED of dexmedetomidine differed significantly between the two groups (P < 0.001). In addition, no significant adverse hemodynamic or hypoxemic effects were noted.
We determined the ED for sedation using intravenous dexmedetomidine adjuvant to PNB in elderly patients. The ED of dexmedetomidine in the middle-old group decreased by 33% compared with that in the young-old group with a mean age difference of 11 years between the two groups.
外周神经阻滞（PNB）中辅助使用镇静剂右美托咪定的半数有效剂量（ED）在老年患者中尚未得到验证。本研究评估了 PNB 辅助下静脉给予右美托咪定在接受全膝关节置换术（TKA）的老年患者中的镇静 ED。
纳入 42 名年龄在 65-85 岁的患者，并根据年龄分为两组：年轻老年组（65-74 岁）和中老年组（75-85 岁）。PNB 完成后，给予预先计算好的右美托咪定剂量，持续 10 分钟。记录观察者警觉/镇静评分、双频谱指数评分、血压和心率。采用 Dixon 上下法和概率单位回归估计右美托咪定辅助 PNB 充分镇静的 ED 值。
年轻老年组单次右美托咪定剂量的 ED 为 0.57μg/kg（95%置信区间，0.47-0.65），中老年组为 0.38μg/kg（95%置信区间，0.28-0.46）。两组之间的 ED 值存在显著差异（P<0.001）。此外，未观察到明显的血流动力学或低氧血症不良影响。
我们确定了 PNB 辅助下静脉给予右美托咪定在老年患者中的镇静 ED。与年轻老年组相比，中老年组的右美托咪定 ED 值降低了 33%，两组平均年龄相差 11 岁。
