混合右美托咪定时羟考酮用于老年病人胃肠道手术后静脉自控镇痛的适宜剂量

Optimal dose of oxycodone for patient-controlled intravenous analgesia after gastrointestinal surgery when combined with dexmedetomidine in elderly patients

目的 确定混合右美托咪定时羟考酮用于老年病人胃肠道手术后静脉自控镇痛（PCIA）的适宜剂量。方法 择期开腹胃肠道肿瘤手术老年病人60例，性别不限，年龄65～80岁，体重50～75 kg，ASA分级Ⅱ或Ⅲ级。采用随机数字表法分为3组（n＝20）。手术结束前15 min，静脉注射羟考酮0.1 mg/kg，同时连接PCIA泵。药物配制：O1组、O2组和O3组分别用右美托咪定2.0 μg/kg混合羟考酮0.3、0.5和0.7 mg/kg，用0.9%生理盐水配成100 ml，背景输注速率2 ml/h，PCA量0.5 ml/次，锁定时间15 min。术后静脉注射羟考酮0.05 mg/kg用于镇痛补救，采用长海尺痛法评估术后疼痛情况，维持长海尺痛评分≤4分。记录术后48 h内PCIA有效按压次数和镇痛补救情况，计算镇痛补救率。观察术后恶心、呕吐、头晕、呼吸抑制、嗜睡、心动过缓、低血压、镇静过度等的发生情况，记录术后72 h时镇痛满意度和术后住院时间。结果 与O1组比较，O2组和O3组术后镇痛补救率降低，PCIA有效按压次数减少，镇痛满意度升高，O3组恶心和嗜睡的发生率增加（P〈0.05）；与O2组比较，O3组术后镇痛补救率和PCIA有效按压次数差异无统计学意义（P〉0.05），术后恶心和嗜睡的发生率增加（P〈0.05）。结论 混合右美托咪定2.0 μg/kg时羟考酮用于老年病人胃肠道手术后PCIA的适宜剂量为0.5 mg/kg。

Objective To determine the optimal dose of oxycodone for patient-controlled intravenous analgesia（PCIA）after gastrointestinal surgery when combined with dexmedetomidine in elderly patients.Methods Sixty patients of both sexes, aged 65-80 yr, weighing 50-75 kg, of American Society of Anesthesiologists physical status Ⅱor Ⅲ, undergoing elective open gastrointestinal surgery, were divided into 3 different doses of oxycodone groups（group O1, group O2 and group O3,n=20 each）using a random number table.At 15 min before the end of surgery, oxycodone 0.1 mg/kg was intravenously injected, and PCIA pump was connected simultaneously.In O1, O2 and O3 groups, the PCIA solution contained dexmedetomidine 2.0 μg/kg and oxycodone 0.3, 0.5 and 0.7 mg/kg in 100 ml of 0.9% normal saline, respectively.The PCIA pump was set up to deliver a 0.5 ml bolus dose with a 15-min lockout interval and background infusion at 2 ml/h.Oxycodone 0.05 mg/kg was intravenously injected as a rescue analgesic after surgery, postoperative pain was assessed using a verbal rating scale, and the verbal rating scale score was maintained ≤4.The number of successfully delivered doses and requirement for rescue analgesics were recorded within 48 h after surgery, and the rate of rescue analgesia was calculated.The occurrence of adverse reactions such as nausea, vomiting, dizziness, respiratory depression, somnolence, bradycardia, hypotension and over-sedation was recorded.Patients′ satisfaction with analgesia at postoperative 72 h and the length of postoperative hospital stay were also recorded.Results Compared with group O1, the rate of rescue analgesia after surgery and the number of successfully delivered doses were significantly decreased, and the degree of patients′ satisfaction with analgesia was increased in O2 and O3 groups, and the incidence of nausea and somnolence was significantly increased in group O3（P〈0.05）. Compared with group O2, no significant change was found in the rate of rescue analgesia after surgery or the number of successfully delivered doses（P〉0.05）, and the incidence of nausea and somnolence was increased in group O3（P〈0.05）.Conclusion When combined with dexmedetomidine 2.0 μg/kg, the optimal dose of oxycodone for PCIA is 0.5 mg/kg after gastrointestinal surgery in elderly patients.