Department of Anesthesiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology Trivandrum, Kerala-695011, India.
J Neurosurg Anesthesiol. 2009 Oct;21(4):297-301. doi: 10.1097/ANA.0b013e3181ac7a31.
Scalp infiltration with epinephrine-lidocaine solution in patients undergoing neurosurgery may result in transient but significant hypotension. We investigated whether premedication with alpha2-adrenoreceptor agonist clonidine, which also exhibits alpha1-adrenoreceptor mediated vasoconstriction, would prevent or attenuate this fall in mean arterial pressure (MAP).
Sixty-six American Society of Anesthesiologists I and II adult patients, 18 to 50 years, undergoing elective tumor decompression were recruited into this prospective, randomized, double-blind, placebo controlled study, and scheduled to receive either oral pantoprazole 40 mg (placebo group) or oral clonidine 3 microg/kg (clonidine group), 90 minutes before induction of anesthesia. Primary end points studied were heart rate (HR) and MAP in both groups measured just before scalp infiltration (preinfiltration baseline) and then every 30 seconds for 5 minutes after initiation of scalp infiltration with 2.5 microg/mL epinephrine contained in 15 mL of 1% lidocaine solution.
There was no significant change in HR in the 2 groups during the study period compared with baseline values; however, patients in clonidine group had significantly lower HR compared with placebo (*P<0.05). In both groups, MAP fell significantly below baseline 1 minute after start of infiltration. It recovered in the clonidine group after 2.5 minutes but not in the placebo group where it continued to remain low even at 5 minutes. MAP in the placebo group was also significantly lower compared with the clonidine group from 2.5 minutes to 5 minutes.
In conclusion, oral clonidine 3 microg/kg administered 90 minutes before induction of anesthesia attenuates the fall in MAP due to scalp infiltration with a dilute concentration of epinephrine-lidocaine solution in patients undergoing craniotomy under isoflurane anesthesia.
在接受神经外科手术的患者头皮浸润肾上腺素-利多卡因溶液可能导致短暂但显著的低血压。我们研究了预先用 α2-肾上腺素能受体激动剂可乐定预处理是否可以预防或减轻这种平均动脉压 (MAP) 的下降，可乐定也表现出 α1-肾上腺素能受体介导的血管收缩。
66 名美国麻醉医师协会 I 和 II 级成年患者，年龄 18 至 50 岁，择期行肿瘤减压，被纳入这项前瞻性、随机、双盲、安慰剂对照研究，并计划接受口服泮托拉唑 40mg（安慰剂组）或口服可乐定 3μg/kg（可乐定组），在麻醉诱导前 90 分钟。主要研究终点为两组患者在头皮浸润前即刻（浸润前基线）以及头皮浸润开始后每 30 秒测量一次心率（HR）和 MAP，头皮浸润使用 1%利多卡因溶液中的 2.5μg/mL 肾上腺素 15ml。
与基线值相比，两组患者在研究期间的 HR 没有明显变化；然而，可乐定组患者的 HR 明显低于安慰剂组（*P<0.05）。两组患者的 MAP 在浸润开始后 1 分钟均显著低于基线值。在可乐定组，MAP 在 2.5 分钟后恢复，但在安慰剂组，MAP 持续较低，甚至在 5 分钟时仍未恢复。在 2.5 分钟至 5 分钟时，安慰剂组的 MAP 也明显低于可乐定组。
总之，在异氟醚麻醉下行颅骨切开术的患者，麻醉诱导前 90 分钟口服 3μg/kg 可乐定可减轻头皮浸润低浓度肾上腺素-利多卡因溶液引起的 MAP 下降。
