Objective

To characterize and compare two intramuscular drug protocols using alfaxalone and alfaxalone–medetomidine combination for the field immobilization of free-ranging koalas.

Study design

Blinded, randomized, comparative field study.

Animals

A total of 66 free-ranging koalas from the Mount Lofty Ranges, South Australia.

Methods

Koalas were randomly allocated into two groups. Group A animals were given alfaxalone alone at 3.5 mg kg^–1. Group AM animals were given alfaxalone 2 mg kg^–1 and medetomidine 40 μg kg^–1, reversed with atipamezole at 0.16 mg kg^–1. Blinded operators recorded heart rate (HR), respiratory rate (f_R), cloacal temperature, depth of sedation and times to: first effect, sedation suitable for clinical interventions, first arousal and full recovery. Data were analysed using independent t test, Mann–Whitney U test, chi-square analysis and log-rank test at 5% level of significance.

Results

Suitable immobilization for clinical examination and sample collection was achieved in all animals. In groups A and AM, median time to working depth was 6.5 minutes (range: 3.4–15) and 8.1 minutes (range: 4.3–24) and time to complete recovery was 66 minutes (range: 12–138) and 34 minutes (range: 4–84), respectively, following reversal. Time to first effect was significantly shorter in group A (p = 0.013), whereas time to full arousal was significantly shorter in group AM (p = 0.007) probably due to the administration of atipamezole. Maximum HR was 117 ± 28 beats minute^–1 in group A, which was a significant increase from baseline values (p < 0.0001), whereas group AM showed a significant tachypnoea of 67 ± 25 (normal f_R 10–15; p < 0.0001).

Conclusions and clinical relevance

Both the protocols produced immobilization, enabling clinical examination and sample collection; however, protocol AM was more suitable for field work due to shorter recovery times.

中文翻译：

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在自由放养的无尾熊（Phascolarctos cinereus）中使用苜蓿草酮和苜蓿草酮-美托咪定进行田间固定：一项随机比较研究。

目的

为了表征和比较两种使用阿法沙酮和阿法沙酮-美托咪定的肌肉注射药物方案在野外无尾熊的固定化方面的作用。

学习规划

盲法，随机，比较性实地研究。

动物

南澳大利亚Mount Lofty Ranges共有66只自由放养的考拉。

方法

考拉被随机分为两组。A组动物单独给予阿尔法沙酮3.5 mg kg ^-1。组AM动物给予alfaxalone 2毫克千克^-1和40美托咪定微克千克^-1，在0.16毫克公斤阿替美唑颠倒^-1。盲人操作者记录以下各项的心率（HR），呼吸频率（f _R），泄殖腔温度，镇静深度和时间：首次作用，适合临床干预的镇静作用，首次唤醒和完全康复。使用独立t检验，Mann-Whitney U检验，卡方分析和对数秩检验以5％的显着性水平分析数据。

结果

在所有动物中都实现了用于临床检查和样品收集的合适固定。在A组和AM组中，达到工作深度的中值时间为6.5分钟（范围：3.4-15）和8.1分钟（范围：4.3-24），完成恢复的时间为66分钟（范围：12-138）和34分钟（范围：4–84），分别在反转之后。A组达到首次起效的时间明显缩短（p  = 0.013），而AM组达到完全唤醒的时间则明显缩短（p  = 0.007），这可能是由于使用了安替他唑。A组的最大HR为117±28次/分– ¹，较基线值有显着增加（p <0.0001），而AM组的显着呼吸急促为67±25（正常f_R 10-15；p <0.0001）。

结论与临床意义

两种方案均产生了固定作用，可以进行临床检查和样品采集；但是，由于恢复时间较短，协议AM更适合于现场工作。