A clinical study on the effect in horses during medetomidine-isoflurane anaesthesia, of butorphanol constant rate infusion on isoflurane requirements, on cardiopulmonary function and on recovery characteristics

作者：Bettschart Wolfen**erger Regula^*; Dicht Sidonia; Vullo Cecilia; Frotzler Angela; Kuemmerle Jan M; Ringer Simone K

来源：Veterinary Anaesthesia and Analgesia, 2011, 38(3): 186-194.

DOI：10.1111/j.1467-2995.2011.00600.x

• anaesthesia
• butorphanol
• horse
• isoflurane
• medetomidine

Objective
To test if the addition of butorphanol by constant rate infusion (CRI) to medetomidine-isoflurane anaesthesia reduced isoflurane requirements, and influenced cardiopulmonary function and/or recovery characteristics.
Study design
Prospective blinded randomised clinical trial.
Animals
61 horses undergoing elective surgery.
Methods
Horses were sedated with intravenous (IV) medetomidine (7 mu g kg-1); anaesthesia was induced with IV ketamine (2.2 mg kg-1) and diazepam (0.02 mg kg-1) and maintained with isoflurane and a CRI of medetomidine (3.5 mu g kg-1 hour-1). Group MB (n = 31) received butorphanol CRI (25 mu g kg-1 IV bolus then 25 mu g kg-1 hour-1); Group M (n = 30) an equal volume of saline. Artificial ventilation maintained end-tidal CO(2) in the normal range. Horses received lactated Ringer's solution 5 mL kg-1 hour-1, dobutamine < 1.25 mu g kg-1 minute-1 and colloids if required. Inspired and exhaled gases, heart rate and mean arterial blood pressure (MAP) were monitored continuously; pH and arterial blood gases were measured every 30 minutes. Recovery was timed and scored. Data were analyzed using two way repeated measures anova, independent t-tests or Mann-Whitney Rank Sum test (p < 0.05).
Results
There was no difference between groups with respect to anaesthesia duration, end-tidal isoflurane (MB: mean 1.06 +/- SD 0.11, M: 1.05 +/- 0.1%), MAP (MB: 88 +/- 9, M: 87 +/- 7 mmHg), heart rate (MB: 33 +/- 6, M: 35 +/- 8 beats minute-1), pH, PaO(2) (MB: 19.2 +/- 6.6, M: 18.2 +/- 6.6 kPa) or PaCO(2.) Recovery times and quality did not differ between groups, but the time to extubation was significantly longer in group MB (26.9 +/- 10.9 minutes) than in group M (20.4 +/- 9.4 minutes).
Conclusion and clinical relevance
Butorphanol CRI at the dose used does not decrease isoflurane requirements in horses anaesthetised with medetomidine-isoflurane and has no influence on cardiopulmonary function or recovery.

• 出版日期2011-5