Objective: To compare the median effective dose (ED50) of intranasal dexmedetomidine for procedural sedation in uncooperative pediatric patients with acyanotic congenital heart disease before and after cardiac surgery.
Methods: We prospectively recruited 47 children (22 in preoperative group and 25 in postoperative group) who needed sedation for transthoracic echocardiography (TTE). A modified up-and-down sequential study design was employed to determine dexmedetomidine dose for each patient with a starting dose of 2 μg/kg in both groups; dexmedetomidine doses for subsequent subjects were determined according to the responses from the previous subject using the up-and-down method at a 0.25 μg/kg interval. The ED95 was determined using probit regression. The onset time, examination time, wake-up time and adverse effects were measured, and the safety was evaluated in terms of changes in vital signs every 5 min.
Results: The ED50 value of intranasal dexmedetomidine for sedation was 1.84 μg/kg (95% CI: 1.68-2.00 μg/kg) in children with congenital heart disease before cardiac surgery, and 3.38 μg/kg (95% CI: 3.21-3.54 μg/kg) after the surgery. No significant difference was found between the two groups in the demographic variables, onset time, examination time, wake-up time, or adverse effects.
Conclusions: In children with acyanotic congenital heart disease, the ED50 of intranasal dexmedetomidine for TTE sedation increases to 3.38 μg/ kg after cardiac surgery from the preoperative value of 1.84 μg/kg.
目的: 确定和比较右美托嘧啶滴鼻镇静用于患有非紫绀性先天性心脏病的儿童心脏手术前后的半数有效剂量。
方法: 本文前瞻性地招募了47名（术前组22名，术后组25名）需要镇静进行经胸心脏彩超检查的儿童。采用Dixon序贯法探究ED50，设定初始剂量为2.0 μg/kg，如果镇静失败，则该组下一位患者右美托嘧啶的剂量增加0.25 μg/kg。如果患儿镇静成功，则该组下一位患者右美托嘧啶的剂量减少0.25 μg/kg，当每组有6个由失败到成功的转折点时终止实验。之后运用Dixon-Massey法计算每组患儿的ED50，此外我们还使用概率回归法推测了ED95。实验中我们同时记录了药物起效时间，检查时间，唤醒时间和不良反应。每5 min根据检测1次生命体征以评估患儿安全。
结果: 两组的患儿在年龄、体质量、禁食时间、失眠率、体温等一般情况上的差异均无统计学意义（P>0.05）。两组的起效时间，检查时间，唤醒时间，不良反应发生率等方面的差异也没有统计学差异（P>0.05）。基于Dixon序贯法的计算结果为：术前组的ED50值为1.84 μg/kg（95%CI，1.68~2.00 μg/kg），术后组ED50为3.38 μg/kg（95%CI，3.21~3.54 μg/kg）（P < 0.05）。基于保序回归的计算结果为：术前组的ED50和ED95值分别为1.79 μg/kg（95%CI，1.49~ 2.00 μg/kg）和2.18 μg/kg（95%CI，1.96~2.23 μg/kg）（P < 0.01）；术后组ED50和ED95值分别为3.32 μg/kg（95%CI，3.08~3.50 μg/kg）和3.68 μg/kg（95%CI，3.47~3.73 μg/kg）（P < 0.01）。
结论: 非紫绀性先心病患儿心脏术前右美托嘧啶镇静半数有效剂量为1.84 μg/kg，术后为3.38 μg/kg。
Keywords: acyanotic congenital heart disease; dexmedetomidine; median effective dose; pediatrics; sedation.