Objective

To evaluate the sedative, analgesic and recovery characteristics of two subanaesthetic ketamine doses in combination with dexmedetomidine and methadone for intramuscular sedation in healthy Beagles.

Study design

Randomized, blinded, crossover, experimental study.

Animals

Six healthy adult Beagles.

Methods

Dogs were randomly given three treatments: dexmedetomidine (3 μg kg^–1) and methadone (0.3 mg kg^–1) combined with ketamine at 1 and 2 mg kg^–1 (K1 and K2, respectively) or saline (K0), intramuscularly. Sedation score, response to tail clamping and rectal temperature were recorded at baseline, 5, 15, 25, 35, and 45 minutes posttreatment. Pulse rate (PR), respiratory rate, oxygen haemoglobin saturation and noninvasive blood pressure were also recorded at baseline and every 5 minutes until 45 minutes posttreatment. Onset and duration of recumbency, response to venous catheterization and recovery quality were also assessed. Sedation and physiological variables were compared between treatments and within treatments compared to baseline (analysis of variance). Nonparametric data were analysed with the Friedman and Cochran’s Q tests; p < 0.050.

Results

Increased sedation was found at 15 (K0 and K1), 25 (all treatments) and 35 (K1) minutes compared with baseline. Sedation score, onset (3–12 minutes) and duration of recumbency (29–51 minutes) were similar between treatments. Recovery quality was considered acceptable in all cases. Response to tail clamping was inconsistent within treatments with no differences between them. None of the dogs responded to venous catheterization. There were no differences between treatments in physiological variables, except for PR which was higher in K2 than in K0. Oxygen supplementation was required in five and three dogs administered saline and ketamine, respectively.

Conclusions and clinical relevance

The addition of 1 or 2 mg kg^–1 of ketamine to methadone and dexmedetomidine combination did not enhance sedation or antinociception in healthy dogs. Recovery quality was unaffected.

中文翻译：

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两种亚麻醉剂量氯胺酮联合美沙酮和低剂量右美托咪定对健康犬的镇静和镇痛作用

客观的

评估两种亚麻醉剂量的氯胺酮联合右美托咪定和美沙酮对健康比格犬肌肉注射镇静的镇静、镇痛和恢复特性。

学习规划

随机、盲法、交叉、实验研究。

动物

六只健康的成年小猎犬。

方法

狗随机接受三种治疗：右美托咪定 (3 μg kg ^–1 ) 和美沙酮 (0.3 mg kg ^–1 ) 联合氯胺酮 1 和 2 mg kg ^–1（分别为 K1 和 K2）或生理盐水（K0），肌肉注射。在基线、治疗后 5、15、25、35 和 45 分钟记录镇静评分、对夹尾的反应和直肠温度。脉率 (PR)、呼吸频率、血红蛋白氧饱和度和无创血压也在基线和每 5 分钟记录一次，直到治疗后 45 分钟。还评估了卧床的发作和持续时间、对静脉导管插入术的反应和恢复质量。比较治疗之间和治疗内与基线相比的镇静和生理变量（方差分析）。非参数数据采用 Friedman 和 Cochran 的 Q 检验进行分析；p < 0.050。

结果

与基线相比，在 15（K0 和 K1）、25（所有治疗）和 35（K1）分钟时发现镇静作用增加。治疗之间的镇静评分、起效（3-12 分钟）和卧床持续时间（29-51 分钟）相似。在所有情况下，恢复质量都被认为是可以接受的。对夹尾的反应在处理中不一致，它们之间没有差异。没有一只狗对静脉导管插入有反应。除了 K2 比 K0 更高的 PR 外，生理变量的处理之间没有差异。分别给予盐水和氯胺酮的五只和三只狗需要补充氧气。

结论和临床相关性

在美沙酮和右美托咪定组合中添加 1 或 2 mg kg ^-1氯胺酮不会增强健康犬的镇静或镇痛作用。恢复质量不受影响。