小剂量氯胺酮辅助全身麻醉对术后疼痛的影响

Effect of combined general anesthesia with small-dose ketamine on postoperative pain

目的观察小剂量氯胺酮辅助全身麻醉对术后疼痛的影响。方法40例择期行腹部手术患者，ASAⅠ～Ⅲ级，年龄29岁～83岁，按随机数目表法随机分为两组，每组20例。氯胺桐组（KG组）：诱导后氯胺酮0．5mg/μg，持续泵注5μg·kg4·min^-1至手术结束；生理盐水对照组（CG组）：持续泵注等容量的生理盐水。两组均采用咪达唑仑0．03mg／1（鼬芬太尼2．0μg／kg、维库溴铵0．1mg，kg、丙泊酚1mg／kg～2mg／kg相同的麻醉诱导；瑞芬太尼和七氟烷维持麻醉并至关腹时停用。记录监测：入室后、诱导前、诱导后、插管即刻、切皮、关腹和拔管时血流动力学变化和脑电双频指数（BIS）值；术毕清醒时间和拔管时间；术后不同时间点镇痛评分、曲马多用量。结果KG组在拔管后第10、15分钟的口述描绘疼痛评分（verbal ratings cales，VRS）比CG组低（2．3±0．6、2．8±0．8，P〈0．05；2．8±0．5、3．4±0．5，P〈0．01）；术后两组首次追加曲马多的时间比较，CG组明显提前（13．5±2．9、9．8±2．5，P〈0．05），两组复苏室曲马多累积用量组间比较差异有统计学意义（75±26、131±29，P〈0．01）。结论术中持续使用小剂量氯胺酮，能减轻术后疼痛评分，减少曲马多用量，提示小剂量氯胺酮对临床相关浓度瑞芬太尼所诱发的术后痛觉过敏具有预防作用。

Objective To observe the effect of combined general anesthesia with small-dose ketamine on postoperative pain. Methods Fourty patients aged 29 y-83 y （ASA Ⅰ -Ⅲ ） scheduled for major abdominal surgery were randomly assigned to receive intraoperative low-dose ketamine （KG group, bolus dose of 0.5 mg/kg followed by continuous infusion of 5 μg· kg·min^-1） or an equal volume of saline （CG group） during remifentanil/sevoflurane anesthesia. Anesthesia was induced with midazolam 0.03 mg/kg, fentanyl 2 μg/kg, vecuronium 0.1 mg/kg, and propofol 1 mg/kg-2 mg/kg. The data of hemodynamics and Bispectral index of the electroencephalogram were recorded at following time points： before induction, after induction, intubation, skin incision, abdomen closure and extubation Awakening time and extubation time were recorded. Pain scores, sedation scores and postoperative tramodal consumption were recored as well. Results The VRS in KG group at 10, 15 min after extubation were lower than that in CG group （2.3±0.6, 2.8±0.8, P〈0.05; 2.8±0.5, 3.4±0.5, P〈0.01）. The first request for tramadol in CG group was earlier than in KG group （13.5±2.9, 9.8±2.5, P〈0.05）. Tramadol consumption in PACU of CG group was much more than that of KG group（75±26, 131±29, P〈0.01）. Conclusions Intraoperative low-dose ketamine infusion could lighten postoperative pain and decrease tramodal consumption. These data suggest that small-dose ketamine could prevent postoperative hyperalgesia induced by clinical concentrations of remifentanil.