Objective

To evaluate the effects of combined infusions of vatinoxan and dexmedetomidine on inhalant anesthetic requirement and cardiopulmonary function in dogs.

Study design

Prospective experimental study.

Methods

A total of six Beagle dogs were anesthetized to determine sevoflurane minimum alveolar concentration (MAC) prior to and after an intravenous (IV) dose (loading, then continuous infusion) of dexmedetomidine (4.5 μg kg^–1 hour^–1) and after two IV doses of vatinoxan in sequence (90 and 180 μg kg^–1 hour^–1). Blood was collected for plasma dexmedetomidine and vatinoxan concentrations. During a separate anesthesia, cardiac output (CO) was measured under equivalent MAC conditions of sevoflurane and dexmedetomidine, and then with each added dose of vatinoxan. For each treatment, cardiovascular variables were measured with spontaneous and controlled ventilation. Repeated measures analyses were performed for each response variable; for all analyses, p < 0.05 was considered significant.

Results

Dexmedetomidine reduced sevoflurane MAC by 67% (0.64 ± 0.1%), mean ± standard deviation in dogs. The addition of vatinoxan attenuated this to 57% (0.81 ± 0.1%) and 43% (1.1 ± 0.1%) with low and high doses, respectively, and caused a reduction in plasma dexmedetomidine concentrations. Heart rate and CO decreased while systemic vascular resistance increased with dexmedetomidine regardless of ventilation mode. The co-administration of vatinoxan dose-dependently modified these effects such that cardiovascular variables approached baseline.

Conclusions and clinical relevance

IV infusions of 90 and 180 μg kg^–1 hour^–1 of vatinoxan combined with 4.5 μg kg^–1 hour^–1 dexmedetomidine provide a meaningful reduction in sevoflurane requirement in dogs. Although sevoflurane MAC-sparing properties of dexmedetomidine in dogs are attenuated by vatinoxan, the cardiovascular function is improved. Doses of vatinoxan >180 μg kg^–1 hour^–1 might improve cardiovascular function further in combination with this dose of dexmedetomidine, but beneficial effects on anesthesia plane and recovery quality may be lost.

中文翻译：

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右美托咪定和vatinoxan输注对七氟醚麻醉犬最低肺泡浓度和心肺功能的联合影响

客观的

评估联合输注vatinoxan和右美托咪定对犬吸入麻醉剂需求和心肺功能的影响。

学习规划

前瞻性实验研究。

方法

在静脉 (IV) 剂量（装载，然后连续输注）右美托咪定（4.5 μg kg ^–1小时^–1）之前和之后以及两次静脉注射后，总共麻醉了 6 只比格犬以确定七氟醚最小肺泡浓度（MAC）vatinoxan 的剂量顺序（90 和 180 μg kg ^–1小时^–1）。收集血液用于血浆右美托咪定和vatinoxan浓度。在单独的麻醉期间，在七氟醚和右美托咪定的等效 MAC 条件下测量心输出量 (CO)，然后在每次添加剂量的 vatinoxan 时测量心输出量 (CO)。对于每次治疗，心血管变量均通过自主通气和受控通气进行测量。对每个响应变量进行重复测量分析；对于所有分析，p < 0.05 被认为是显着的。

结果

右美托咪定使七氟醚 MAC 降低了 67% (0.64 ± 0.1%)，狗的平均值 ± 标准偏差。在低剂量和高剂量下，加入伐替诺生分别将其减弱至 57% (0.81 ± 0.1%) 和 43% (1.1 ± 0.1%)，并导致血浆右美托咪定浓度降低。无论通气模式如何，右美托咪定都可降低心率和 CO，而全身血管阻力增加。vatinoxan 的共同给药剂量依赖性地改变了这些效应，使得心血管变量接近基线。

结论和临床相关性

静脉输注 90 和 180 μg kg ^–1小时^–1的vatinoxan 结合 4.5 μg kg ^–1小时^–1右美托咪定可显着降低狗的七氟醚需求。尽管 vatinoxan 减弱了狗中右美托咪定的七氟醚 MAC 保留特性，但心血管功能得到了改善。剂量 >180 μg kg ^–1小时^–1的伐替诺沙与该剂量的右美托咪定联合使用可能会进一步改善心血管功能，但可能会失去对麻醉平面和恢复质量的有益影响。