Comparison Between Medetomidine and a Medetomidine-Vatinoxan Combination on Cardiorespiratory Variables in Dogs Undergoing Ovariectomy Anesthetized with Butorphanol, Propofol and Sevoflurane or Desflurane

Abstract

The aim of this study was to compare the effects of a medetomidine-vatinoxan combination versus medetomidine alone on heart rate (HR) and mean arterial pressure (MAP) in a short-term surgery in dogs. Four groups of 10 dogs were administered as follows: medetomidine and sevoflurane; medetomidine and desflurane; medetomidine-vatinoxan and sevoflurane; and medetomidine-vatinoxan and desflurane. After administration, the increase in MAP soon stopped at 102-104 mmHg in the two groups administered medetomidine-vatinoxan, compared with significantly higher values of 143-126 mmHg achieved in the two groups administered medetomidine alone. The lowest MAPs in the two medetomidine-vatinoxan groups were 46-50 mmHg, while in the medetomidine groups, they were 58-79 mmHg. From 3 min onwards after administration, in the medetomidine-vatinoxan treatments, HR remained at values very close to those of pre-administration, between 83 and 118 beats min^-1, while in the medetomidine treatments, it dropped to 36-43 beats min^-1 and then slowly rose to reach 71-90 beats min^-1. These results encourage the use of vatinoxan in clinical settings, particularly in anesthetic protocols for dogs when bradycardia and an increase in systemic pressure should be avoided. Further clinical studies are needed to manage the short periods of hypotension, as well as the slight reduction in sedative and pain-relieving medetomidine effects found, particularly when vatinoxan is in combination with desflurane rather than sevoflurane.

Keywords: anesthesia; dog; heart rate; inhalant agents; mean arterial blood pressure; medetomidine; monitoring; recovery score; sedation; vatinoxan.

Figure 1

Line graph for median, first quartile (Q1), and third quartile (Q3) of mean arterial blood pressure (MAP) in dogs before anesthesia induction (T−1) and before (T0) and after (T1–T9) administration with medetomidine 0.25 mg m⁻² and sevoflurane (Mede-Sevo) (n = 10), medetomidine 0.25 mg m⁻² and desflurane (Mede-Des) (n = 10), medetomidine 0.25 mg m⁻² + vatinoxan 5 mg m⁻² and sevoflurane (Vati-Sevo) (n = 10), medetomidine 0.25 mg m⁻² + vatinoxan 5 mg m⁻² and desflurane (Vati-Des) (n = 10) during ovariectomy (T6–T9). Time points from T−1 to T9 are plotted along chronological time from 20 min before administration to 50 min after.

Figure 2

Line graph for median, first quartile (Q1), and third quartile (Q3) of heart rate (HR) in dogs before anesthesia induction (T−1) and before (T0) and after (T1–T9) administration with medetomidine 0.25 mg m⁻² and sevoflurane (Mede-Sevo) (n = 10), medetomidine 0.25 mg m⁻² and desflurane (Mede-Des) (n = 10), medetomidine 0.25 mg m⁻² + vatinoxan 5 mg m⁻² and sevoflurane (Vati-Sevo) (n = 10), medetomidine 0.25 mg m⁻² + vatinoxan 5 mg m⁻² and desflurane (Vati-Des) (n = 10) during ovariectomy (T6–T9). Time points from T−1 to T9 are plotted along chronological time from 20 min before administration to 50 min after.

Figure 3

Box and whisker plot for recovery score at one minute after extubation in dogs undergoing ovariectomy administered with medetomidine 0.25 mg m⁻² and sevoflurane (Mede-Sevo) (n = 10), medetomidine 0.25 mg m⁻² and desflurane (Mede-Des) (n = 10), medetomidine 0.25 mg m⁻² + vatinoxan 5 mg m⁻² and sevoflurane (Vati-Sevo) (n = 10), medetomidine 0.25 mg m⁻² + vatinoxan 5 mg m⁻² and desflurane (Vati-Des) (n = 10). The light blue rectangular box (Mede-Des) represents the interquartile range (IQR), spanning from the first quartile (Q1) to the third quartile (Q3), with a line inside indicating the median. In the blue rectangular box (Vati-Des), the median and Q1 overlap. In the green and orange lines (Mede-Sevo and Vati-Sevo, respectively), the median, Q1, and Q3 overlap. The whiskers extend from the box’s edges and denote the non-outlier extremes. Any data points outside this range are considered outliers and are depicted as individual dots.