Ouchi Kentaro, Sugiyama Kazuna
From the Department of Dental Anesthesiology, Field of Oral and Maxillofacial Rehabilitation, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.
Reg Anesth Pain Med. 2016 May-Jun;41(3):348-55. doi: 10.1097/AAP.0000000000000380.
Dexmedetomidine (DEX) dose dependently enhances the local anesthetic action of lidocaine in rats. We hypothesized that the effect might also be dose dependent in humans. We evaluated the effect of various concentrations of DEX with a local anesthetic in humans.
Eighteen healthy volunteers were randomly assigned by a computer to receive 1.8 mL of 1 of 4 drug combinations: (1) 1% lidocaine with 2.5 ppm (parts per million) (4.5 μg) DEX, (2) lidocaine with 5.0 ppm (9.0 μg) DEX, (3) lidocaine with 7.5 ppm (13.5μg) DEX, or (4) lidocaine with 1:80,000 (22.5 μg) adrenaline (AD), to produce inferior alveolar nerve block. Pulp latency and lower lip numbness (for assessing onset and duration of anesthesia) were tested, and sedation level, blood pressure, and heart rate were recorded every 5 minutes for 20 minutes, and every 10 minutes from 20 to 60 minutes.
Pulp latency of each tooth increased compared with baseline, from 5 to 15 minutes until 60 minutes. There were no significant intergroup differences at any time point. Anesthesia onset was not different between groups. Anesthesia duration was different between groups (that with DEX 7.5 ppm was significantly longer than that with DEX 2.5 ppm and AD; there was no difference between DEX 2.5 ppm and AD). Blood pressure decreased from baseline in the 5.0 and 7.5 ppm DEX groups at 30 to 60 minutes, although there was no hypotension; moreover, heart rate did not change in any group. Sedation score did not indicate deep sedation in any of the groups.
Dexmedetomidine dose dependently enhances the local anesthetic action of lidocaine in humans. Dexmedetomidine at 2.5 ppm produces similar enhancement of local anesthesia effect as addition of 1:80,000 AD.
右美托咪定（DEX）可剂量依赖性地增强利多卡因在大鼠体内的局部麻醉作用。我们推测这种作用在人类中可能也是剂量依赖性的。我们评估了不同浓度的DEX与局部麻醉药联合使用对人体的影响。
18名健康志愿者通过计算机随机分组，接受4种药物组合之一的1.8 mL药物：（1）含2.5 ppm（百万分之）（4.5μg）DEX的1%利多卡因，（2）含5.0 ppm（9.0μg）DEX的利多卡因，（3）含7.5 ppm（13.5μg）DEX的利多卡因，或（4）含1:80,000（22.5μg）肾上腺素（AD）的利多卡因，以产生下牙槽神经阻滞。测试牙髓潜伏期和下唇麻木情况（用于评估麻醉的起效和持续时间），并在20分钟内每5分钟记录一次镇静水平、血压和心率，并在20至60分钟内每10分钟记录一次。
每颗牙齿的牙髓潜伏期与基线相比均增加，从5分钟到15分钟直至60分钟。在任何时间点组间均无显著差异。各组间麻醉起效无差异。各组间麻醉持续时间不同（含7.5 ppm DEX组明显长于含2.5 ppm DEX组和AD组；含2.5 ppm DEX组与AD组之间无差异）。在3至60分钟时，含DEX 5.0 ppm和7.5 ppm组的血压较基线下降，尽管未出现低血压；此外，任何组的心率均未改变。镇静评分未显示任何组有深度镇静。
右美托咪定可剂量依赖性地增强利多卡因在人体中的局部麻醉作用。2.5 ppm的右美托咪定产生的局部麻醉效果增强与添加1:80,000肾上腺素相似。
