[Dispersion of lidocaine epidurally administered to dogs positioned on lateral or external decubitus]

ABSTRACT The aim of this study was to clinically verify the dispersion of lidocaine in the epidural space of dogs placed in different positions. Sixteen dogs with an average weight of 17.5 kilograms were used. These were tranquilized with acepromazine, anesthetized with propofol and allocated to two groups: sternal decubitus (GE) and right lateral decubitus (GLD). Both groups received 2% of lidocaine in the volume of 0.25mL/kg and remained in the same position for 20 minutes. The blocking of the pelvic limbs and the extension of it from the seventh lumbar vertebra were evaluated by means of interdigital and paravertebral panniculus clamping. Orchiectomy surgery was then performed. Afterwards, the total blocking time of the pelvic limbs was evaluated. All dogs presented bilateral blocking, with no differences in cranial extension between groups, with a median of 7.5 (1-14) vertebrae for GE and 4 (1-14) for GLD. The blocking time of the right and left limbs were 123 ± 26 and 130 ± 20 minutes for GE, and 120 ± 21 and 121 ± 20 minutes for GLD with no difference between groups or between limbs. It is concluded that the decubitus does not interfere with the epidural lidocaine distribution.摘要：本研究旨在临床验证不同体位下犬硬膜外腔（epidural space）中利多卡因（lidocaine）的扩散分布情况。本研究共纳入16只平均体重为17.5千克的实验犬，经乙酰丙嗪（acepromazine）镇静、丙泊酚（propofol）麻醉后，将其分为两组：俯卧位组（sternal decubitus，GE）与右侧卧位组（right lateral decubitus，GLD）；两组均给予体积为0.25mL/kg的2%利多卡因，并保持初始体位20分钟。通过趾间钳夹与椎旁皮褶钳夹试验，评估两组犬的后肢（pelvic limbs）神经阻滞（blocking）效果以及阻滞范围向第7腰椎（seventh lumbar vertebra）头端的延伸程度，随后实施睾丸去势术（orchiectomy），术后评估两组犬后肢神经阻滞的总持续时间。所有实验犬均出现双侧神经阻滞，两组的阻滞头端延伸范围无显著差异：俯卧位组（GE）的阻滞头端中位数为7.5（1~14）个椎体，右侧卧位组（GLD）为4（1~14）个椎体；俯卧位组（GE）的右后肢与左后肢阻滞持续时间分别为123±26分钟、130±20分钟，右侧卧位组（GLD）的右后肢与左后肢阻滞持续时间分别为120±21分钟、121±20分钟，组间及肢体侧别间均无显著差异。综上，体位摆放不会对犬硬膜外腔中利多卡因的扩散分布造成影响。