Use of a continuous, local infusion of bupivacaine for postoperative analgesia in dogs undergoing total ear canal ablation.
OBJECTIVE
To determine whether addition of a continuous, local infusion of bupivacaine would improve postoperative analgesia in dogs undergoing total ear canal ablation.


METHODS
Randomized controlled trial.


METHODS
16 dogs undergoing total ear canal ablation (12 unilaterally and 4 bilaterally with > 1 month between procedures).


METHODS
Dogs were randomly allocated to receive morphine (0.25 mg/kg [0.11 mg/lb]) at the end of the procedure (10 procedures) or morphine and a continuous, local infusion of bupivacaine (0.13 to 0.21 mg/kg/h [0.06 to 0.1 mg/lb/h]; 10 procedures). Dogs were observed for 48 hours after surgery. Additional doses of morphine were administered up to every 4 hours in dogs with signs of severe pain.


RESULTS
Temperament, sedation, analgesia, and cumulative pain scores were not significantly different between groups any time after surgery. Recovery score was significantly higher for dogs that received bupivacaine than for control dogs 2 hours after extubation but not at any other time. Serum cortisol concentration was not significantly different between groups at any time but, in both groups, was significantly increased at the time of extubation, compared with all other observation times. Total number of additional doses of morphine administered was not significantly different between groups. Bupivacaine was not detected in the plasma of any of the dogs that received the local bupivacaine infusion.


CONCLUSIONS
Results suggest that addition of a continuous, local infusion of bupivacaine did not significantly increase the degree of postoperative analgesia in dogs that underwent total ear canal ablation and were given morphine at the end of surgery.
Radlinsky
MaryAnn G
MG
Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506-5606, USA.
Mason
Diane E
DE
Roush
James K
JK
Pineda
Rosalind
R
D000779:Anesthetics, Local / Q000008:administration & dosage / Q000627:therapeutic use*; D000818:Animals; D002045:Bupivacaine / Q000008:administration & dosage / Q000627:therapeutic use*; D004283:Dog Diseases / Q000188:drug therapy* / Q000601:surgery; D004285:Dogs; D004359:Drug Therapy, Combination; D004424:Ear Canal / Q000502:physiology / Q000601:surgery*; D006854:Hydrocortisone / Q000097:blood; D009020:Morphine / Q000627:therapeutic use; D010147:Pain Measurement / Q000662:veterinary; D010149:Postoperative Pain / Q000188:drug therapy / Q000662:veterinary*; D013997:Time Factors; D016896:Treatment Outcome
D000779:Anesthetics, Local; D009020:Morphine; D006854:Hydrocortisone; D002045:Bupivacaine