Thalhammer J G, Vladimirova M, Bershadsky B, Strichartz G R
Department of Anesthesia Research Laboratories, Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
Anesthesiology. 1995 Apr;82(4):1013-25. doi: 10.1097/00000542-199504000-00026.
Quantitative behavioral testing is necessary to establish a reproducible measure of differential functional blockade during regional anesthesia. Methods for assessment of the neurologic status (mental status, posture, gait, proprioception, motor function, autonomic function, and nociception) in veterinary neurology were adapted for the rat and used to monitor functional changes separately during a sciatic nerve block.
Sprague-Dawley rats were acclimated to laboratory routine before the study so that lidocaine (0.1 ml, 1%) could be injected near the sciatic notch without any chemical restraint. The onset, duration, and magnitude of functional losses were monitored. Proprioceptive integrity was evaluated by assessing the response to tactile placing and the hopping response. Extensor postural thrust, a test for postural reactions in small animals, was assessed on a digital balance and found adequate for quantifying motor function. Analgesia was assessed by measuring withdrawal response latencies to noxious thermal stimulation (51 degrees C) and to superficial and deep noxious pinches. Autonomic function was monitored by measuring skin temperature. Contralateral limb function was used as an internal control, and injection of saline was used as an external control in separate, control animals.
Onset of postural and gait abnormalities were observed as early as 40 s after injection. On each occasion proprioceptive impairment was detected first, followed by impairment of motor function and nociception. Complete absence of proprioception occurred from 10 to 30 min (n = 9) and of motor function at 30 min after injection (n = 10); both functions were fully recovered by 120 min. A unilateral increase in skin temperature on the foot was detected by 1 min; had reached its maximum change, 5.3 +/- 0.7 degrees C, at 10 min; and had returned to control levels at 60 min after injection (n = 12). Withdrawal response to cutaneous or superficial pain was absent in all ten animals from 5 to 30 min whereas the response to deep pain was absent in all ten animals at 20 min only. The response to noxious stimulation recovered at 90 min. Attention was paid to the temporal relation of the impairment of various functions.
Quantitative observations of the onset, offset, and intensity of differential functional impairment or block over time will make it possible to establish the doses and conditions for local anesthetics that result in differential nerve block and will permit comparison of these changes among different drugs and "clinical" protocols.
在区域麻醉期间，进行定量行为测试对于建立可重复的不同功能阻滞测量方法是必要的。兽医神经学中评估神经状态（精神状态、姿势、步态、本体感觉、运动功能、自主神经功能和痛觉）的方法被应用于大鼠，并用于在坐骨神经阻滞期间分别监测功能变化。
在研究前，将Sprague-Dawley大鼠适应实验室常规，以便在无需任何化学约束的情况下，在坐骨切迹附近注射利多卡因（0.1 ml，1%）。监测功能丧失的起始、持续时间和程度。通过评估对触觉放置和跳跃反应的应答来评估本体感觉完整性。在数字天平上评估伸肌姿势推力，这是一种用于小动物姿势反应的测试，发现其足以量化运动功能。通过测量对有害热刺激（51摄氏度）以及浅表和深部有害捏压的撤反应潜伏期来评估镇痛效果。通过测量皮肤温度来监测自主神经功能。在单独的对照动物中，将对侧肢体功能用作内部对照，并将注射生理盐水用作外部对照。
注射后最早在40秒时观察到姿势和步态异常的起始。每次都是首先检测到本体感觉受损，随后是运动功能和痛觉受损。注射后10至30分钟（n = 9）本体感觉完全丧失，30分钟时运动功能完全丧失（n = 10）；两种功能在120分钟时均完全恢复。注射后1分钟检测到足部皮肤温度单侧升高；在10分钟时达到最大变化，为5.3±0.7摄氏度；并在注射后60分钟恢复到对照水平（n = 12）。在5至30分钟时，所有十只动物对皮肤或浅表疼痛的撤反应均消失，而仅在20分钟时所有十只动物对深部疼痛的反应消失。对有害刺激的反应在90分钟时恢复。关注了各种功能受损的时间关系。
对不同功能损害或阻滞随时间的起始、消退和强度进行定量观察，将有可能确定导致不同神经阻滞的局部麻醉药的剂量和条件，并将允许比较不同药物和“临床”方案之间的这些变化。
