Comparison of a blind and an ultrasound‐guided technique for Retrobulbar anesthesia in dogs undergoing unilateral subconjunctival enucleation

Objective This study compared the quality of retrobulbar anesthesia using a blind inferior‐temporal palpebral approach (ITP) with an ultrasound‐guided supratemporal (ST) technique in dogs undergoing unilateral enucleation. Animal studied Twenty‐one client‐owned dogs were undergoing enucleation. Procedures Dogs were randomly assigned to receive ITP (n = 10) or ST (n = 11) with 0.5% ropivacaine at 0.1 mL/cm of neurocranial length. The anesthetist was blinded to the technique. Intraoperative data included cardiopulmonary variables, inhalant anesthetics requirement, and requirement for rescue analgesia (intravenous fentanyl 2.5 mcg/kg). Postoperative data included pain scores, sedation scores, and need for intravenous hydromorphone (0.05 mg/kg). Treatments were compared using Wilcoxon's rank sum test or Fisher's exact test as appropriate. Comparison of variables over time were tested using a mixed effect linear model on rank. Significance was set at p = 0.05. Results Intraoperative cardiopulmonary variables and inhalant requirements were not different between groups. Dogs receiving ITP required median (interquartile range, IQR) 1.25 (0, 2.5) mcg/kg intraoperative fentanyl while those receiving ST required none (p