Hoerdemann Mona, Smith Rachael L, Hosgood Giselle
Equine Department, College of Veterinary Medicine, Murdoch University, Perth, Australia.
Small Animal Surgery Department, College of Veterinary Medicine, Murdoch University, Perth, Australia.
Vet Surg. 2017 Oct;46(7):986-993. doi: 10.1111/vsu.12689. Epub 2017 Jul 13.
To establish and compare the onset and duration of action of 2 local anesthetics based on objective lameness and skin sensitivity assessment.
Interventional crossover experimental trial with balanced randomization.
Eight horses.
Reversible forelimb lameness was induced in 8 horses. A palmar digital nerve block (PDNB) was applied with mepivacaine or lidocaine (both 2%). Quantitative lameness and skin sensitivity data were collected with an inertial sensor system and a force gauge, respectively. The times to lameness resolution/skin desensitization (T1), consistent lameness detection/partial return of skin sensitivity (T2), and complete return of lameness/skin sensitivity (T3) were determined and compared between treatments and assessment methods.
Mepivacaine blocks resolved lameness in 8/8 horses, compared to 3/8 horses with lidocaine blocks. Both agents led to skin desensitization in 8/8 horses. Skin desensitization occurred sooner than lameness resolution after mepivacaine (P = .047). Duration of action was longer with mepivacaine than lidocaine (mean T3_lameness mepivacaine 366 minutes, lidocaine 113 minutes (P = .038); T3_skin mepivacaine 195 minutes, lidocaine 63 minutes [P ≤ .001]). Skin sensitivity returned sooner than lameness after lidocaine block at T3 (P = .015).
The use of lidocaine in PDNBs for the purpose of lameness diagnosis should be reassessed, as it may not resolve lameness despite loss of skin sensation. Mepivacaine is superior, with a reliable onset and longer duration of action. Skin desensitization as an indicator for the onset of action or effectiveness of PDNBs for mepivacaine and lidocaine, or as a measure of the duration of action of lidocaine PDNBs should be interpreted with caution.
基于客观跛行和皮肤敏感性评估，建立并比较两种局部麻醉药的起效时间和作用持续时间。
采用平衡随机化的介入性交叉试验。
8匹马。
对8匹马诱导出可逆性前肢跛行。分别用甲哌卡因或利多卡因（均为2%）进行掌指神经阻滞（PDNB）。分别使用惯性传感器系统和测力计收集定量跛行和皮肤敏感性数据。确定并比较两种治疗方法和评估方法之间跛行缓解/皮肤脱敏时间（T1）、持续跛行检测/皮肤敏感性部分恢复时间（T2）以及跛行/皮肤敏感性完全恢复时间（T3）。
甲哌卡因阻滞使8/8匹马的跛行得到缓解，而利多卡因阻滞仅使3/8匹马的跛行得到缓解。两种药物均使8/8匹马的皮肤脱敏。甲哌卡因注射后，皮肤脱敏比跛行缓解出现得更早（P = 0.047）。甲哌卡因的作用持续时间比利多卡因长（甲哌卡因平均T3_跛行时间为366分钟，利多卡因为113分钟[P = 0.038]；甲哌卡因T3_皮肤时间为195分钟，利多卡因为63分钟[P≤0.001]）。在T3时，利多卡因阻滞皮肤敏感性恢复比利多卡因阻滞跛行恢复更早（P = 0.015）。
在用于跛行诊断的掌指神经阻滞中，利多卡因的使用应重新评估，因为尽管皮肤感觉丧失，但它可能无法缓解跛行。甲哌卡因更优，起效可靠且作用持续时间更长。对于甲哌卡因和利多卡因，将皮肤脱敏作为掌指神经阻滞起效或有效性的指标，或作为利多卡因掌指神经阻滞作用持续时间的衡量指标时，应谨慎解读。
