Ruíz-López Patricia, Morgaz Juan, Quirós-Carmona Setefilla, Navarrete-Calvo Rocío, Domínguez Juan Manuel, Gómez-Villamandos Rafael Jesús, Granados M M
Department of Surgery and Anesthesia of Domestic Animals, Faculty of Veterinary Medicine, University of Ghent, 9820 Merelbeke, Belgium.
Animal Medicine and Surgery Department, Faculty of Veterinary Medicine, University of Córdoba, 14014 Cordoba, Spain.
Animals (Basel). 2022 Apr 15;12(8):1038. doi: 10.3390/ani12081038.
Autonomic nervous system (ANS) activity can modify cardiovascular parameters in response to nociceptive stimuli or drugs in anesthetized animals. The aim of this study was to determine if a surgical nociceptive stimulus and morphine, ketamine, and dobutamine administration would modify ANS activity observed as a change in the mean parasympathetic tone activity (PTAm) in anesthetized horses. In 20 anesthetized horses, heart rate (HR), mean arterial pressure (MAP), and PTAm were monitored before and 1, 3, and 5 min after surgical incision, and before and 10 min after the administration of morphine (0.2 mg/kg IV). If nystagmus or spontaneous ventilation was observed, ketamine (0.5 mg/kg IV) was given, and the three variables were registered before and 3 and 5 min afterward. If MAP reached ≤62 mmHg, a dobutamine infusion was administered, and the three variables were recorded before and 5 min after starting/increasing the infusion (0.25 μg/kg/min IV every 5 min). The three variables were registered before and 1, 3, and 5 min after a PTAm decrease of ≥20%, HR increase of ≥10%, or MAP increase of ≥20%. The PTAm decreased 3 min after the administration of ketamine and 1 min after a PTA event. The surgical incision, dobutamine, and morphine did not modify PTAm. The absence of changes in ANS activity after the nociceptive stimulus and lack of correlation between PTAm and HR or MAP suggest that PTAm is a poor indicator of sympathetic activation under the study conditions. Ketamine seems to affect ANS activity by decreasing PTAm.
自主神经系统（ANS）的活动可在麻醉动物中响应伤害性刺激或药物而改变心血管参数。本研究的目的是确定手术伤害性刺激以及吗啡、氯胺酮和多巴酚丁胺的给药是否会改变麻醉马匹中观察到的自主神经系统活动，这种活动表现为平均副交感神经张力活动（PTAm）的变化。在20匹麻醉马匹中，于手术切口前以及切口后1、3和5分钟监测心率（HR）、平均动脉压（MAP）和PTAm，并且在静脉注射吗啡（0.2mg/kg）前以及注射后10分钟进行监测。如果观察到眼球震颤或自主呼吸，则静脉注射氯胺酮（0.5mg/kg），并在给药前以及给药后3和5分钟记录这三个变量。如果MAP降至≤62mmHg，则给予多巴酚丁胺输注，并在开始/增加输注前（0.25μg/kg/min静脉注射，每5分钟一次）以及输注后5分钟记录这三个变量。在PTAm降低≥20%、HR升高≥10%或MAP升高≥20%后1、3和5分钟记录这三个变量。氯胺酮给药后3分钟以及PTA事件后1分钟PTAm降低。手术切口、多巴酚丁胺和吗啡并未改变PTAm。伤害性刺激后自主神经系统活动未发生变化，且PTAm与HR或MAP之间缺乏相关性，这表明在本研究条件下PTAm并非交感神经激活的良好指标。氯胺酮似乎通过降低PTAm来影响自主神经系统活动。
