Objective

To determine the alfaxalone dose reduction during total intravenous anaesthesia (TIVA) when combined with ketamine or midazolam constant rate infusions and to assess recovery quality in healthy dogs.

Study design

Prospective, blinded clinical study.

Animals

A group of 33 healthy, client-owned dogs subjected to dental procedures.

Methods

After premedication with intramuscular acepromazine 0.05 mg kg^-1 and methadone 0.3 mg kg^-1, anaesthetic induction started with intravenous alfaxalone 0.5 mg kg^-1 followed by either lactated Ringer’s solution (0.04 mL kg^-1, group A), ketamine (2 mg kg^-1, group AK) or midazolam (0.2 mg kg^-1, group AM) and completed with alfaxalone until endotracheal intubation was achieved. Anaesthesia was maintained with alfaxalone (6 mg kg^-1 hour^-1), adjusted (±20%) every 5 minutes to maintain a suitable level of anaesthesia. Ketamine (0.6 mg kg^-1 hour^-1) or midazolam (0.4 mg kg^-1 hour^-1) were employed for anaesthetic maintenance in groups AK and AM, respectively. Physiological variables were monitored during anaesthesia. Times from alfaxalone discontinuation to extubation, sternal recumbency and standing position were calculated. Recovery quality and incidence of adverse events were recorded. Groups were compared using parametric analysis of variance and nonparametric (Kruskal-Wallis, Chi-square, Fisher’s exact) tests as appropriate, p < 0.05.

Results

Midazolam significantly reduced alfaxalone induction and maintenance doses (46%; p = 0.034 and 32%, p = 0.012, respectively), whereas ketamine only reduced the alfaxalone induction dose (30%; p = 0.010). Recovery quality was unacceptable in nine dogs in group A, three dogs in group AK and three dogs in group AM.

Conclusions and clinical relevance

Midazolam, but not ketamine, reduced the alfaxalone infusion rate, and both co-adjuvant drugs reduced the alfaxalone induction dose. Alfaxalone TIVA allowed anaesthetic maintenance for dental procedures in dogs, but the quality of anaesthetic recovery remained unacceptable irrespective of its combination with ketamine or midazolam.

中文翻译：

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氯胺酮或咪达唑仑连续速率输注对健康犬苜蓿总静脉麻醉的要求和恢复质量的影响：一项随机临床试验。

目的

为了确定氯胺酮或咪达唑仑恒速输注与全静脉麻醉（TIVA）时阿尔法鲍宁的剂量降低，并评估健康犬的恢复质量。

学习规划

前瞻性，盲法临床研究。

动物

一组33只健康的，由客户拥有的狗，他们接受了牙科手术。

方法

用肌内注射乙酰丙嗪0.05 mg kg ^-1和美沙酮0.3 mg kg ^-1进行处方前，先静脉内注射苜蓿草酮0.5 mg kg ^-1进行麻醉诱导，然后用乳酸林格氏液（0.04 mL kg ^-1，A组），氯胺酮（2 mg kg ^-1，AK组）或咪达唑仑（0.2 mg kg ^-1，AM组），并用曲沙酮完成直至气管插管。用曲沙酮（6 mg kg ^{-1 -1}小时^-1）维持麻醉，每5分钟调整一次（±20％）以维持适当的麻醉水平。氯胺酮（0.6 mg kg ^-1小时^-1）或咪达唑仑（0.4 mg kg ^-1小时^-1）在组AK和AM分别用于麻醉维护。在麻醉期间监测生理变量。计算了从紫杉醇停药到拔管的时间，胸骨卧位和站立姿势。记录恢复质量和不良事件的发生率。使用方差的参数分析和非参数（Kruskal-Wallis，卡方，费舍尔精确）检验对各组进行比较，p <0.05。

结果

咪达唑仑显着降低了阿法沙酮的诱导和维持剂量（分别为46％；p  = 0.034和32％，p  = 0.012），而氯胺酮仅降低了阿法沙酮的诱导剂量（30％；p  = 0.010）。A组中的九只狗，AK组的三只狗和AM组的三只狗的恢复质量是不能接受的。

结论与临床意义

咪达唑仑，但不是氯胺酮，降低了阿法沙酮的输注速度，两种辅助药物均降低了阿法沙酮的诱导剂量。Alfaxalone TIVA可以对狗进行牙科手术进行麻醉维持，但是无论其与氯胺酮或咪达唑仑的组合使用，麻醉恢复的质量仍然不可接受。