McLeod G A, Dale J, Robinson D, Checketts M, Columb M O, Luck J, Wigderowitz C, Rowley D
University Department of Anaesthesia, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK.
Br J Anaesth. 2009 Apr;102(4):528-33. doi: 10.1093/bja/aep010. Epub 2009 Feb 24.
Infusion of local anaesthetic through femoral and sciatic catheters is an accepted method of providing pain relief after knee arthroplasty. However, the minimum effective concentration of perineural local anaesthetics is not known.
Twenty-four patients received femoral and sciatic perineural infusions of levobupivacaine in order to prevent pain relief after total knee arthroplasty. The primary endpoint of the study was patient request for analgesic rescue for anterior or posterior knee pain within the first 36 h of perineural infusion. Treatment was determined by the method of sequential allocation, with a dosing interval of 0.002% w/v.
Thirteen patients did not require rescue analgesia for anterior knee pain and 16 patients did not require rescue analgesia for posterior knee pain. Median duration of failed blocks until rescue analgesia was 25 h (24-27 h) for the femoral block and 27 h (24-29 h) for the sciatic block. The minimum concentration at which patients did not require rescue analgesia was 0.024% for the femoral nerve and 0.014% for the sciatic nerve. Comparison of EC(50) showed that local anaesthetic requirements were significantly (P=0.03) higher by a factor of 1.25 (95% CI 1.03-1.55) for the femoral compared with the sciatic nerve.
The EC(50) for femoral perineural infusion is greater than the EC(50) for sciatic perineural infusion.
通过股神经和坐骨神经导管输注局部麻醉剂是膝关节置换术后提供疼痛缓解的一种公认方法。然而，神经周围局部麻醉剂的最低有效浓度尚不清楚。
24例患者接受股神经和坐骨神经周围输注左旋布比卡因，以预防全膝关节置换术后的疼痛缓解。该研究的主要终点是在神经周围输注的前36小时内患者因膝前或膝后疼痛而要求使用镇痛补救药物。治疗采用序贯分配法确定，给药间隔为0.002% w/v。
对于膝前疼痛，13例患者不需要补救镇痛；对于膝后疼痛，16例患者不需要补救镇痛。股神经阻滞至补救镇痛失败的中位持续时间为25小时（24 - 27小时），坐骨神经阻滞为27小时（24 - 29小时）。患者不需要补救镇痛的最低浓度，股神经为0.024%，坐骨神经为0.014%。半数有效浓度（EC(50)）的比较显示，与坐骨神经相比，股神经的局部麻醉剂需求量显著更高（P = 0.03），高出1.25倍（95%可信区间1.03 - 1.55）。
股神经周围输注的EC(50)大于坐骨神经周围输注的EC(50)。
