Objective

To investigate the impact of intramuscular (IM) co-administration of the peripheral α₂-adrenoceptor agonist vatinoxan (MK-467) with medetomidine and butorphanol prior to intravenous (IV) ketamine on the cardiopulmonary and anaesthetic effects in dogs, followed by atipamezole reversal.

Study design

Randomized, masked crossover study.

Animals

A total of eight purpose-bred Beagle dogs aged 3 years.

Methods

Each dog was instrumented and administered two treatments 2 weeks apart: medetomidine (20 μg kg^–1) and butorphanol (100 μg kg^–1) premedication with vatinoxan (500 μg kg^–1; treatment MVB) or without vatinoxan (treatment MB) IM 20 minutes before IV ketamine (4 mg kg^–1). Atipamezole (100 μg kg^–1) was administered IM 60 minutes after ketamine. Heart rate (HR), mean arterial (MAP) and central venous (CVP) pressures and cardiac output (CO) were measured; cardiac (CI) and systemic vascular resistance (SVRI) indices were calculated before and 10 minutes after MVB or MB, and 10, 25, 40, 55, 70 and 100 minutes after ketamine. Data were analysed with repeated measures analysis of covariance models. A p-value <0.05 was considered statistically significant. Sedation, induction, intubation and recovery scores were assessed.

Results

At most time points, HR and CI were significantly higher, and SVRI and CVP significantly lower with MVB than with MB. With both treatments, SVRI and MAP decreased after ketamine, whereas HR and CI increased. MAP was significantly lower with MVB than with MB; mild hypotension (57–59 mmHg) was recorded in two dogs with MVB prior to atipamezole administration. Sedation, induction, intubation and recovery scores were not different between treatments, but intolerance to the endotracheal tube was observed earlier with MVB.

Conclusions and clinical relevance

Haemodynamic performance was improved by vatinoxan co-administration with medetomidine–butorphanol, before and after ketamine administration. However, vatinoxan was associated with mild hypotension after ketamine with the dose used in this study. Vatinoxan shortened the duration of anaesthesia.

中文翻译：

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美托咪定和布托啡诺合用肌内伐他沙生（MK-467）对犬静脉内氯胺酮的心肺和麻醉作用。

目的

为了研究肌内（IM）的联合给药的影响的周边α ₂ -肾上腺素受体激动剂vatinoxan（MK-467）用美托咪定和布托啡诺之前对犬心肺和麻醉作用静脉内（IV）氯胺酮，随后逆转阿替美唑。

学习规划

随机，掩盖的交叉研究。

动物

总共八只3岁的小猎犬犬。

方法

对每只狗进行仪器检查，并间隔2周进行两次治疗：美托咪定（20μgkg ^–1）和布托啡诺（100μgkg ^–1）预先用vatinoxan（500μgkg ^–1；治疗MVB）或不使用vatinoxan（MB治疗）IM静脉注射氯胺酮（4毫克千克^–1）之前20分钟。氯胺酮注射60分钟后，Atipamezole（100μgkg ^–1）给药。测量心率（HR），平均动脉（MAP）和中心静脉（CVP）压力以及心输出量（CO）；在MVB或MB之前和之后10分钟以及氯胺酮后10、25、40、55、70和100分钟后计算心脏（CI）和全身血管阻力（SVRI）指数。通过协方差模型的重复测量分析来分析数据。一个p值<0.05被认为具有统计学意义。评估镇静，诱导，插管和恢复评分。

结果

在大多数时间点，与MB相比，MVB的HR和CI显着较高，而SVRI和CVP显着降低。氯胺酮治疗后，两种治疗方法的SVRI和MAP均降低，而HR和CI升高。MVB的MAP明显低于MB。在服用阿帕米唑之前，两只MVB犬记录有轻度低血压（57-59 mmHg）。两种疗法的镇静，诱导，插管和恢复评分无差异，但使用MVB较早时观察到对气管插管的耐受性差。

结论与临床意义

氯胺酮在氯胺酮给药之前和之后与瓦美多沙合用美托咪定-丁啡诺可改善血液动力学性能。然而，氯胺酮与氯胺酮治疗后的轻度低血压有关。Vatinoxan缩短了麻醉时间。