儿童MRI检查前联合咪达唑仑镇静时右美托咪定的有效剂量测定

Determination of effective dose of dexmedetomidine administered intranasally combined with oral midazolam sedation for pediatric MRI:a modified sequential study

目的测定儿童磁共振成像(MRI)检查前联合咪达唑仑镇静时右美托咪定的有效剂量。方法本研究为前瞻性改良序贯研究。纳入2023年2-3月在浙江大学医学院附属儿童医院接受MRI检查前行镇静的26例患儿,年龄2个月至6岁,体重6.0~23.5 kg。所有患儿给予0.5 mg/kg咪达唑仑口服,再经鼻滴入右美托咪定。采用改良序贯法测定此联合用药时所需右美托咪定的剂量,初始剂量为0.5μg/kg,等差剂量为0.1μg/kg,采用probit回归分析法计算右美托咪定的半数有效剂量(ED50)和95%有效剂量(ED_(95))及相应的95%CI,并记录镇静患儿入睡及苏醒时间、用药前后的生命体征及不良反应。结果所有患儿中,镇静有效患儿的镇静入睡时间为(31.21±7.47)min、苏醒时间为(81.21±26.04)min。MRI检查前镇静中联合0.5 mg/kg咪达唑仑口服时,右美托咪定滴鼻有效镇静的ED50为0.392μg/kg,95%CI为0.302~0.461μg/kg;ED_(95)为0.549μg/kg,95%CI为0.473~0.996μg/kg。镇静有效患儿入睡后的心率、舒张压与给药前基础状态比较,差异有统计学意义(P<0.05)。出现苏醒期躁动2例,无其他不良反应发生。结论右美托咪定滴鼻联合咪达唑仑用药方案无创,便于实行,且安全有效,可在儿童MRI检查中推广应用。

Objective To determine the effective dose of dexmedetomidine administered intranasally combined with oral midazolam sedation before pediatric magnetic resonance image(MRI).Methods This is a prospective modified sequential study.Children scheduled for MRI at the Children's Hospital of Zhejiang University School of Medicine from February to March 2023,aged 1 month to 6 years old,with a weight of 6.0-23.5 kg,were enrolled in this study.All children received 0.5 mg/kg oral midazolam,followed by intranasal dexmedetomidine.The initial dose of dexmedetomidine was 0.5μg/kg,and the intranasal dose of dexmedetomidine was determined using the modified Dixon's up-and-down method with increments or decrements of 0.1μg/kg.Probit analysis was used for calculating the half effective dose(ED50),95%effective dose(ED_(95))and the corresponding 95%confidence interval(CI)of intranasal dexmedetomidine combined with oral midazolam for pediatric sedation during MRI.The sedation onset time,wake-up time,vital signs and adverse reactions were recorded.Results Among all the children,the sedation onset time of successful sedation children was(31.21±7.47)min,and the wake-up time was(81.21±26.04)min.The ED50 for effective sedation with intranasal dexmedetomidine combined with oral medication at a dose of 0.5 mg/kg was calculated to be 0.392μg/kg,with a 95%CI of 0.302-0.461 μg/kg;the ED_(95) was 0.549 μg/kg, with a 95%CI of 0.473-0.996 μg/kg. There was a statistically significant difference (P<0.05) in heart rate and diastolic blood pressure after sedation compared to the baseline before medication. Two cases of restlessness during the awakening period were observed, but no other adverse reactions occurred. Conclusions The sedation regimen of intranasal dexmedetomidine combined with oral midazolam is non-invasive, easy to implement, safe, and effective. It can be widely used in pediatric MRI.