Jellinek H, Haumer H, Grubhofer G, Klappacher G, Jenny T, Weindlmayr-Goettel M, Fitzal S
Universitätsklinik für Anaesthesie und Allgemeine Intensivmedizin, Wien.
Anaesthesist. 1990 Oct;39(10):513-20.
Patient-controlled analgesia (PCA) is a well-proven procedure for individual pain relief in the post-operative period. Despite its superior approach regarding pharmacokinetic and pharmacodynamic considerations, PCA equipment is not available to many in the clinical practice. The goal of this study was to compare the efficacy and safety of PCA with continuous infusion (CI), an easily feasible method, using tramadol (T) as a centrally acting opioid with minor side effects on circulation and ventilation.
The study was conducted on 20 ASA I or II patients aged 20-60 years undergoing gynecological operations under standardized general anesthesia. They were randomly allocated to two groups receiving i.v. T for postoperative pain relief via Lifecare PCA 4200 Infuser. Group 1 (G1, PCA, n = 10): loading dose 3 mg/kg T, demand dose 30 mg T, lock-out time 5 min, concurrent infusion 5 mg/h T; group 2 (G2, CI, n = 10): loading dose 3 mg/kg T, continuous infusion 0.35 mg/kg per h T. If the analgesia was inadequate, additional doses of 50 mg T were available in G2. During a mean trial period of 20 h, the heart rate, blood pressure, respiratory rate and blood gas analysis were documented. The plasma levels of T and beta-endorphins were determined. The quality of analgesia was assessed by using a verbal and a visual analogue scale.
The mean applied doses of T were 339 +/- 100 mg and 364 +/- 46 mg (G1 and G2, respectively) after 6 h and 565 +/- 243 mg and 707 +/- 139 mg (G1 and G2, respectively) in total (NS). Interindividual differences were substantial in G1. Five patients in G2 required an additional dose of 50 mg T. Pain scores decreased rapidly in both groups. The pain relief achieved was comparable and excellent after 6 h. The next morning, G2 reported significantly better analgesia in accordance with the higher availability of T as CI during the sleeping period. Mean plasma T levels were 994 +/- 440 ng/ml and 1170 +/- 357 ng/ml (G1 and G2, respectively). No correlation was found between T-levels and pain scores. The plasma levels of beta-endorphins were substantially elevated after the operation. They returned to normal during T-administration in both groups. No correlation was found between plasma levels of beta-endorphins and pain scores or T-consumption. Hemodynamic changes were minor and without clinical significance. PaO2 and paCO2 remained within small deviations from the physiological range. The respiratory rate, which was initially increased, dropped slightly in both groups. A high incidence of nausea and vomiting was observed, starting in the early phase of the loading dose.
T is well suitable for postoperative pain relief after major gynecological surgery using both PCA and CI. PCA ensures adjustment of the medication to the individual demand, whereas CI provides better analgesia after sleeping periods. We recommend antiemetic prophylaxis before treatment with T.
患者自控镇痛（PCA）是术后个体疼痛缓解的一种经充分验证的方法。尽管在药代动力学和药效学方面具有优势，但临床实践中许多人无法使用PCA设备。本研究的目的是比较PCA与持续输注（CI）（一种易于实施的方法）的疗效和安全性，使用曲马多（T）作为对循环和通气副作用较小的中枢性阿片类药物。
本研究对20例年龄在20 - 60岁、接受标准化全身麻醉下妇科手术的ASA I或II级患者进行。他们被随机分为两组，通过Lifecare PCA 4200输液器静脉注射T用于术后疼痛缓解。第1组（G1，PCA，n = 10）：负荷剂量3 mg/kg T，按需剂量30 mg T，锁定时间5分钟，同时输注5 mg/h T；第2组（G2，CI，n = 10）：负荷剂量3 mg/kg T，持续输注0.35 mg/kg每小时T。如果镇痛不足，G2组可额外给予50 mg T。在平均20小时的试验期内，记录心率、血压、呼吸频率和血气分析。测定T和β-内啡肽的血浆水平。使用语言和视觉模拟量表评估镇痛质量。
6小时后T的平均应用剂量分别为339±100 mg和364±46 mg（分别为G1和G2组），总量分别为565±243 mg和707±139 mg（分别为G1和G2组）（无显著性差异）。G1组个体差异较大。G2组有5名患者需要额外给予50 mg T。两组疼痛评分均迅速下降。6小时后实现的疼痛缓解相当且良好。第二天早上，G2组报告镇痛效果明显更好，这与睡眠期间CI组T的可用性更高一致。平均血浆T水平分别为994±440 ng/ml和1170±357 ng/ml（分别为G1和G2组）。未发现T水平与疼痛评分之间存在相关性。术后β-内啡肽的血浆水平显著升高。两组在给予T期间均恢复正常。未发现β-内啡肽的血浆水平与疼痛评分或T消耗量之间存在相关性。血流动力学变化较小且无临床意义。PaO2和PaCO2与生理范围的偏差较小。最初升高的呼吸频率在两组中均略有下降。观察到恶心和呕吐的发生率较高，从负荷剂量的早期阶段开始。
T适用于使用PCA和CI的大型妇科手术后的术后疼痛缓解。PCA可确保根据个体需求调整用药，而CI在睡眠期后提供更好的镇痛效果。我们建议在使用T治疗前进行抗呕吐预防。
