From the Department of Anaesthesia, Centre of Head and Orthopaedics, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
Outcomes Research Consortium, Cleveland, Ohio.
Anesth Analg. 2018 Jun;126(6):2069-2077. doi: 10.1213/ANE.0000000000002747.
Based on the assumption that relatively large volumes of local anesthetic optimize an adductor canal block (ACB), we theorized that an ACB administered as repeated boluses would improve analgesia without compromising mobility, compared with a continuous infusion.
We performed a randomized, blinded, controlled study, including patients scheduled for total knee arthroplasty with spinal anesthesia. Patients received 0.2% ropivacaine via a catheter in the adductor canal administered as either repeated intermittent boluses (21 mL/3 h) or continuous infusion (7 mL/h). The primary outcome was total (postoperative day [POD], 0-2) opioid consumption (mg), administered as patient-controlled analgesia. Pain, ambulation, and quadriceps muscle strength were secondary outcomes.
We randomized 110 patients, of whom 107 were analyzed. Total opioid consumption (POD, 0-2) was a median (range) of 23 mg (0-139) in the bolus group and 26 mg (3-120) in the infusion group (estimated median difference, 4 mg; 95% confidence interval [CI], -13 to 5; P = .29). Linear mixed-model analyses revealed no difference in pain during knee flexion (mean difference, 2.6 mm; 95% CI, -2.9 to 8.0) or at rest (mean difference, 1.7 mm; 95% CI, -1.5 to 4.9). Patients in the bolus group had improved quadriceps sparing on POD 2 (median difference, 7.4%; 95% CI, 0.5%-15.5%). However, this difference was not present on POD 1 or reflected in the ambulation tests (P > .05).
Changing the mode of administration for an ACB from continuous infusion to repeated intermittent boluses did not decrease opioid consumption, pain, nor mobility.
基于局部麻醉药的较大容量可优化收肌管阻滞（ACB）的假设，我们推测与连续输注相比，以重复间歇推注方式给予 ACB 可在不影响活动能力的情况下改善镇痛效果。
我们进行了一项随机、盲法、对照研究，纳入了接受椎管内麻醉下全膝关节置换术的患者。患者接受 0.2%罗哌卡因经收肌管导管给药，方式为重复间歇推注（21 mL/3 h）或连续输注（7 mL/h）。主要结局是术后 0-2 天（POD）的总（POD，0-2）阿片类药物消耗（mg），通过患者自控镇痛给药。次要结局为疼痛、活动能力和股四头肌肌力。
我们随机分配了 110 例患者，其中 107 例患者进行了分析。推注组的总阿片类药物消耗（POD，0-2）中位数（范围）为 23 mg（0-139），输注组为 26 mg（3-120）（估计中位数差值，4 mg；95%置信区间[CI]，-13 至 5；P =.29）。线性混合模型分析显示，在膝关节屈曲时（平均差值，2.6 mm；95%CI，-2.9 至 8.0）或休息时（平均差值，1.7 mm；95%CI，-1.5 至 4.9），两组之间的疼痛无差异。推注组在 POD 2 时的股四头肌保护作用改善（中位数差值，7.4%；95%CI，0.5%-15.5%）。然而，在 POD 1 或活动能力测试中并未发现这种差异（P >.05）。
将 ACB 的给药方式从连续输注改为重复间歇推注并未减少阿片类药物消耗、疼痛或活动能力。
