Helayel Pablo Escovedo, Conceição Diogo Brüggemann da, Knaesel Julian Alexander, Ceccon Maurício Sperotto, Mago Adilson José Dal, Oliveira Filho Getúlio Rodrigues de
NEPAR, CET, SBA.
Rev Bras Anestesiol. 2009 Sep-Oct;59(5):521-30. doi: 10.1016/s0034-7094(09)70077-7.
The volume and mass of local anesthetics (LA) affect the success rate of peripheral nerve blocks. Thus, the main objective of this study was to determine the volumes of local anesthetics in parasacral and infragluteal-parabiceps sciatic nerve block (SNB).
One hundred and one patients undergoing infragluteal-parabiceps or parasacral SNB with 0.5% ropivacaine or 0.5% bupivacaine with 5 microg.mL-1 of adrenaline were randomly divided into 4 groups. Success was defined as complete sensitive and motor blockades of the sciatic nerve 30 minutes after the administration of the LA. Volumes were calculated by the up-and-down method.
In the parasacral approach, the mean effective volume of ropivacaine was 17.6 mL (95% CI: 14.9-20.8) and of bupivacaine it was 16.4 mL (95% CI: 12.3-21.9). In the infragluteal-parabiceps approach, the mean effective volume of ropivacaine was 21.8 mL (95% CI: 18.7-25.5), and that of bupivacaine was 20.4 mL (95% CI: 18.6-22.5). Volumes were significantly lower (p < 0.01) in the parasacral than in the infragluteal-parabiceps approach. In Probit regression, the estimated effective volume in 95% of the patients in the parasacral approach was 21.8 mL for ropivacaine, and 20.5 mL for bupivacaine; in the infragluteal-parabiceps approach the volumes were 27.2 mL for ropivacaine and 25.5 mL for bupivacaine. The effective volume in 99% of the patients in parasacral SNB was 24 mL for ropivacaine, and 24 mL for bupivacaine; and in the infragluteal-parabiceps approach, 29.9 mL for ropivacaine, and 28.0 mL for bupivacaine.
In sciatic nerve block, significantly smaller volumes were necessary in the parasacral than in the infragluteal-parabiceps approach, but volumes did not differ between both LAs.
局部麻醉药（LA）的容量和质量会影响周围神经阻滞的成功率。因此，本研究的主要目的是确定骶旁和臀下-肱二头肌坐骨神经阻滞（SNB）中局部麻醉药的容量。
101例接受臀下-肱二头肌或骶旁SNB的患者，使用含5μg·mL-1肾上腺素的0.5%罗哌卡因或0.5%布比卡因，随机分为4组。成功定义为在给予局部麻醉药30分钟后坐骨神经完全感觉和运动阻滞。容量通过上下法计算。
在骶旁入路中，罗哌卡因的平均有效容量为17.6 mL（95%CI：14.9-20.8），布比卡因的平均有效容量为16.4 mL（95%CI：12.3-21.9）。在臀下-肱二头肌入路中，罗哌卡因的平均有效容量为21.8 mL（95%CI：18.7-25.5），布比卡因的平均有效容量为20.4 mL（95%CI：18.6-22.5）。骶旁入路的容量显著低于（p<0.01）臀下-肱二头肌入路。在概率回归中，骶旁入路中95%患者的罗哌卡因估计有效容量为21.8 mL，布比卡因为20.5 mL；在臀下-肱二头肌入路中，罗哌卡因的容量为27.2 mL，布比卡因为25.5 mL。骶旁SNB中99%患者的罗哌卡因有效容量为24 mL，布比卡因为24 mL；在臀下-肱二头肌入路中，罗哌卡因的容量为29.9 mL，布比卡因为28.0 mL。
在坐骨神经阻滞中，骶旁入路所需的容量明显小于臀下-肱二头肌入路，但两种局部麻醉药所需的容量没有差异。
