Savla Jyothi R, Ghai Babita, Bansal Dipika, Wig Jyotsna
Department of Anaesthesia and Intensive Care, Post Graduate Institute of Medical Education and Research, Chandigarh, India.
Paediatr Anaesth. 2014 Apr;24(4):433-9. doi: 10.1111/pan.12358. Epub 2014 Jan 28.
This study was conducted to determine the effect of oral midazolam (OM) or intranasal dexmedetomidine (IND) on the EC50 of sevoflurane for successful laryngeal mask airway placement in children. We hypothesize that premedication with either agent might reduce the sevoflurane EC50 for laryngeal mask airway placement in children to a similar extent.
Fifty-two American Society of Anesthesiologists (ASA) I children (aged 1-6 years) scheduled for general anesthesia with laryngeal mask airway were randomized to one of the three groups: group M received 0.5 mg · kg(-1) OM with honey and intranasal saline, group D received 2 μg · kg(-1) IND along with oral honey, and group P received oral honey and intranasal saline at least 30 min prior to induction of anesthesia. Anesthesia was induced with incremental sevoflurane up to 8% in 100% O2 . A predetermined target endtidal sevoflurane (ETsevo ) concentration (2% in the first child of all three groups) was sustained for 10 min before the attempt of laryngeal mask airway insertion by adjusting dial concentration. No intravenous anesthetic or neuromuscular blockade was used. ETsevo was increased/decreased (step size 0.2%) using Dixon's and Massey's up and down method in next patient depending upon previous patient's response. Placement of the laryngeal mask airway without movement, coughing, biting, or bucking was considered as successful. EC50 of sevoflurane was calculated as the average of the crossover midpoints in each group, which was further confirmed by probit analysis.
The EC50 of sevoflurane for laryngeal mask airway placement after OM (1.66 ± 0.31) and IND (1.57 ± 0.14) premedications was significantly lower than the placebo group (2.00 ± 0.17, P < 0.0001). The EC95 (95% CI) derived from probit regression analysis was 2.34% (2.22-2.51%) with OM, 1.88% (1.77-2.04%) with IND, and 2.39% (2.25-2.35%) with placebo group.
Oral midazolam and IND premedications significantly reduce the sevoflurane EC50 for laryngeal mask airway insertion in children by 17% and 21%, respectively.
本研究旨在确定口服咪达唑仑（OM）或鼻内右美托咪定（IND）对七氟醚在儿童成功置入喉罩气道时的半数有效浓度（EC50）的影响。我们假设，这两种药物中的任何一种进行术前用药，都可能在相似程度上降低七氟醚用于儿童喉罩气道置入时的EC50。
52例计划接受喉罩气道全麻的美国麻醉医师协会（ASA）I级儿童（年龄1 - 6岁）被随机分为三组之一：M组接受0.5 mg·kg⁻¹的OM加蜂蜜和鼻内生理盐水；D组接受2 μg·kg⁻¹的IND加口服蜂蜜；P组在麻醉诱导前至少30分钟接受口服蜂蜜和鼻内生理盐水。在100%氧气中用递增的七氟醚诱导麻醉，最高至8%。在尝试置入喉罩气道前，通过调整刻度浓度，将预定的目标呼气末七氟醚（ETsevo）浓度（三组中第一个儿童为2%）维持10分钟。未使用静脉麻醉药或神经肌肉阻滞剂。根据前一位患者的反应，在下一位患者中使用狄克逊（Dixon）和梅西（Massey）上下法增加/降低ETsevo（步长0.2%）。喉罩气道置入时无肢体移动、咳嗽、咬或挣扎被视为成功。七氟醚的EC50计算为每组交叉中点的平均值，并通过概率分析进一步确认。
OM（1.66 ± 0.31）和IND（1.57 ± 0.14）术前用药后，七氟醚用于喉罩气道置入的EC50显著低于安慰剂组（2.00 ± 0.17，P < 0.0001）。概率回归分析得出的EC95（95%CI），OM组为2.34%（2.22 - 2.51%），IND组为1.88%（1.77 - 2.04%），安慰剂组为2.39%（2.25 - 2.35%）。
口服咪达唑仑和IND术前用药分别使七氟醚用于儿童喉罩气道置入的EC50显著降低17%和21%。
