Comparison of bupivacaine and dexmedetomidine femoral and sciatic nerve blocks with bupivacaine and buprenorphine epidural injection for stifle arthroplasty in dogs

ObjectiveTo compare the quality of anesthesia and analgesia from femoral and sciatic nerve blocks (FS) with bupivacaine and dexmedetomidine with that from an epidural injection (EPI) with bupivacaine and buprenorphine in dogs undergoing unilateral stifle arthroplasty. Study designProspective, blinded, randomized, clinical comparison. AnimalsTwenty-six dogs weighing 3610kg and aged 5 (1-11) years. MethodsDogs were randomly assigned to either FS [n=13; bupivacaine 0.5% (0.5mgkg(-1)) plus dexmedetomidine (0.1gkg(-1)) for each nerve] or EPI [n=13; bupivacaine 0.5% (1mgkg(-1)) plus buprenorphine (4gkg(-1))]. Data collected included intraoperative cardiopulmonary variables and postoperative pain scores (Glasgow Composite Pain Scale), sedation scores, opioid consumption, time to urination and time to return of various behaviors. Rescue analgesia (hydromorphone 0.05mgkg(-1)) was administered intravenously whenever pain scores were 6/24. Subsequent data from rescued dogs were excluded from further analysis. ResultsNo differences were found for any of the variables evaluated during and after anesthesia. Over 60% (nine dogs in FS, eight dogs in EPI) of patients from either group did not need additional analgesia within the 24hour observational period. Three and four patients in FS and EPI, respectively, that required rescue analgesia did so within the first 30minutes after extubation; only one patient in EPI required supplemental analgesia more than 4hours after extubation. One patient in each group did not urinate spontaneously for 24hours. Conclusions and clinical relevanceBoth techniques have the potential to provide sufficient analgesia for up to 24hours in approximately two-thirds of dogs. Careful observation for signs of pain and preparedness to intervene is still recommended. The incidence of urinary retention was low in both groups. These techniques show promise for providing high-quality analgesia for stifle arthroplasty.