Effect of detomidine or romifidine constant rate infusion on plasma lactate concentration and inhalant requirements during isoflurane anaesthesia in horses.

This research study explored the impact of detomidine or romifidine constant rate infusion (CRI) on plasma lactate concentration and isoflurane requirements in horses during surgery. The findings revealed that neither detomidine nor romifidine CRI produced a significant increase in plasma lactate compared with a control group, and both infusions lowered the requirement for isoflurane during surgery.

Research Methodology

• The study was conducted as a prospective, randomized, blinded, clinical trial involving 24 adult healthy horses.
• In preparation for anesthesia, all horses were given acepromazine and either intravenous detomidine (group D), romifidine (group R), or xylazine (group C, the control).
• Different medications were administered during surgery. Group D received a detomidine CRI in a lactate Ringer’s solution (LRS), group R received romifidine CRI in LRS, and group C obtained an equal quantity of LRS.
• Anesthesia was induced with ketamine and diazepam and maintained with isoflurane in oxygen.
• Blood samples for assessing plasma lactate were collected prior to anesthesia (baseline), during surgery (three samples at 30-minute intervals), and in recovery (at 10 minutes, once standing, and 3 hours after anesthesia).
• The end-tidal isoflurane percentage (Fe’Iso) was also measured and classified into three periods: Prep, Surgery 1, and Surgery 2.
• A linear mixed model was used for data analysis, with p-values less than 0.05 being interpreted as significant.

Research Findings

• The study showed a difference in plasma lactate between the baseline and once standing in all three groups. However, the values did not significantly vary between the groups.
• In groups D and R, there was a significant decrease (by 18% and 15%, respectively) in Fe’Iso during Surgery 2, as compared with the control group (group C).

Conclusions

• The study concluded that the intraoperative use of detomidine or romifidine CRIs in horses did not result in clinically significant increases in plasma lactate compared to the control group.
• Moreover, the infusions of detomidine and romifidine decreased the need for isoflurane during surgical procedures, indicating their effectiveness in anesthesia provision.