The effect of cervical epidural injection of morphine and the combination of morphine and detomidine on recovery from anesthesia in adult horses.

OBJECTIVE

To evaluate the effect of cervical epidural injection of morphine alone and morphine in combination with detomidine on recovery from anesthesia in horses.

STUDY

DESIGN

Blinded, randomized, crossover, Latin square design.

ANIMALS: A group of six healthy adult horses aged 9 ± 3 years and weighing 471 ± 76 kg (mean ± standard deviation).

METHODS

Horses were administered each of three treatments during a 1 hour general anesthetic with a 4 day washout period. Treatments were: 1) cervical epidural injection of saline 0.011 mL kg-1 (S); 2) morphine 0.1 mg kg-1 (M); and 3) morphine 0.1 mg kg-1 with detomidine 0.01 mg kg-1 (MD). Data evaluating the quality of rope-assisted anesthetic recovery included accelerometry-based recovery score, time to first movement, time to sternal recumbency, time to standing and number of attempts to stand. Data were analyzed using a generalized linear mixed model. Significance was set at p < 0.05.

RESULTS

Recovery scores were 24.4 ± 10.0, 23.9 ± 6.7 and 19.9 ± 7.7 for treatments S, M and MD, respectively (p = 0.463). Times for first movement, sternal recumbency and standing were 33 ± 16, 22 ± 18 and 45 ± 10 minutes; 48 ± 26, 57 ± 29 and 69 ± 25 minutes; and 55 ± 20, 61 ± 28 and 70 ± 23 minutes for treatments S, M and MD, respectively.

CONCLUSIONS

Cervical epidural injection of morphine alone and morphine with detomidine did not negatively affect recovery compared with saline.

CLINICAL RELEVANCE: The use of cervical epidural injection of morphine alone or morphine in combination with detomidine does not negatively affect the recovery quality of horses from general anesthesia.