Menzies M Paula Larenza, Ringer Simone K, Conrot Aude, Theurillat Regula, Kluge Katharina, Kutter Annette Pn, Jackson Michelle, Thormann Wolfgang, Bettschart-Wolfensberger Regula
Section of Anaesthesiology, Equine Department, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
Clinical Pharmacology Laboratory, Institute for Infectious Diseases, University of Berne, Berne, Switzerland.
Vet Anaesth Analg. 2016 Nov;43(6):623-634. doi: 10.1111/vaa.12359. Epub 2016 Feb 25.
To evaluate cardiopulmonary effects and anaesthesia recovery quality in horses anaesthetized with isoflurane receiving medetomidine or S-ketamine infusions.
Randomized, blinded, prospective clinical trial.
Fifty horses undergoing elective surgery.
After acepromazine and flunixin meglumine premedication, horses received medetomidine (7 μg kg ) intravenously (IV). Anaesthesia was induced with midazolam and racemic ketamine (Med treatment group; 2.2 mg kg ; n = 25) or S-ketamine (S-ket treatment group; 1.1 mg kg ; n = 25) IV and maintained with isoflurane in oxygen/air and medetomidine (Med; 3.5 μg kg hour ) or S-ketamine (S-ket; 0.5 mg kg hour ). All horses were mechanically ventilated. Cardiopulmonary variables were evaluated. Isoflurane end-tidal concentrations (Fe'Iso), dobutamine requirements and thiopental boli were recorded. Plasma samples were collected in six horses to evaluate S-ketamine and S-norketamine concentrations. After surgery, medetomidine 2 μg kg was administered IV. Four independent observers scored recovery using a visual analogue scale and a numerical rating scale.
Both groups required similar mean Fe'Iso (1%). However, S-ket horses needed more thiopental boli. Median intraoperative cardiac index values were higher with S-ket (4.5 L minute m ) than Med (3.9 L minute m ). Overall, there were no differences in heart rate, blood pressure or dobutamine requirements; however, horses in S-ket showed higher heart rate values at 30 minutes after anaesthesia induction. Compared with Med horses, S-ket horses showed decreased PaO and increased pulmonary venous admixture values estimated with the Fshunt calculation. Recoveries were shorter and of poorer quality with S-ket. During infusion, S-ketamine and S-norketamine plasma concentrations lay in the ranges of 0.209-0.917 μg mL and 0.250-0.723 μg mL , respectively.
Despite the higher intraoperative cardiac index with S-ket, both protocols were considered to provide acceptable cardiovascular function. However, recovery quality was significantly better in the Med group.
评估接受美托咪定或S-氯胺酮输注的异氟烷麻醉马匹的心肺效应和麻醉恢复质量。
随机、双盲、前瞻性临床试验。
50匹接受择期手术的马匹。
在给予乙酰丙嗪和氟尼辛葡甲胺进行术前用药后，马匹静脉注射美托咪定（7μg/kg）。麻醉诱导采用咪达唑仑和消旋氯胺酮（美托咪定治疗组；2.2mg/kg；n = 25）或S-氯胺酮（S-氯胺酮治疗组；1.1mg/kg；n = 25）静脉注射，并用异氟烷在氧气/空气中维持麻醉，同时持续输注美托咪定（美托咪定组；3.5μg/kg·小时）或S-氯胺酮（S-氯胺酮组；0.5mg/kg·小时）。所有马匹均进行机械通气。评估心肺变量。记录异氟烷呼气末浓度（Fe'Iso）、多巴酚丁胺需求量和硫喷妥钠推注量。采集6匹马的血浆样本以评估S-氯胺酮和S-去甲氯胺酮浓度。手术后，静脉注射2μg/kg美托咪定。4名独立观察者使用视觉模拟量表和数字评分量表对恢复情况进行评分。
两组所需的平均Fe'Iso相似（1%）。然而，S-氯胺酮组的马匹需要更多的硫喷妥钠推注量。S-氯胺酮组术中心脏指数中位数（4.5L/分钟·m²）高于美托咪定组（3.9L/分钟·m²）。总体而言，心率、血压或多巴酚丁胺需求量无差异；然而，S-氯胺酮组的马匹在麻醉诱导后30分钟时心率值较高。与美托咪定组马匹相比，S-氯胺酮组马匹的PaO₂降低，通过F分流计算估计的肺静脉混合血值增加。S-氯胺酮组的恢复时间更短且质量更差。在输注过程中，S-氯胺酮和S-去甲氯胺酮的血浆浓度分别在0.209 - 0.917μg/mL和0.250 - 0.723μg/mL范围内。
尽管S-氯胺酮组术中心脏指数较高，但两种方案均被认为能提供可接受的心血管功能。然而，美托咪定组的恢复质量明显更好。
