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. 2024 Jan;27(1):79-85.
doi: 10.1111/vop.13092. Epub 2023 Apr 6.

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

Jessica D Briley  1 , Demitrius Washington  2 , Hans D Westermeyer  3 , Lysa P Posner  1 , Ludovica Chiavaccini  4
Affiliations

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

Jessica D Briley et al. Vet Ophthalmol. 2024 Jan.

Abstract

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 < 0.01). Intraoperative fentanyl was required in 5/10 and 0/11 of dogs in the ITP and ST groups, respectively (p = 0.01). Postoperative analgesia requirements were not significantly different between groups; 2/10 and 1/10 dogs in the ITP and ST groups, respectively. Sedation score negatively affected pain score (p < 0.01).

Conclusions: The ultrasound-guided ST technique was more effective at decreasing intraoperative opioid requirements than the blind ITP approach in dogs undergoing unilateral enucleation.

Keywords: analgesia; dogs; enucleation; retrobulbar; ropivacaine; ultrasound-guided.

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References

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