At the investigated doses dobutamine improved systemic and peripheral haemodynamics, while dopamine decreased MAP and peripheral perfusion. Noradrenaline increased MAP and SVR while peripheral blood flow was maintained, phenylephrine increased MAP, but reduced both local and systemic perfusion.

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A 2-year, 10-month-old male entire whippet had an epidural catheter placed to provide postoperative analgesia following lateral thoracotomy. He received 0.1 mg/kg preservative free morphine every 12 hours via the epidural catheter. After the fifth dose, the dog showed sudden signs of pruritus and myoclonus and became severely distressed, and the epidural catheter was removed. Despite initial treatment with sedatives (dexmedetomidine and propofol), antihistamines (chlorphenamine) and the opioid antagonist naloxone, the pruritus did not completely resolve. Ten hours after the onset of clinical signs, having received additional sedation (dexmedetomidine) and supportive treatment, the dog returned to normal behaviour and the pruritus stopped. The dog subsequently recovered uneventfully. Pruritus and myoclonus following epidural administration of morphine can be difficult to manage and may appear after several doses have been administered.

Objective: There is limited knowledge regarding the safety and accuracy of ultrasound-guided retrobulbar nerve blocks in horses. The aim of this study was to compare these parameters between blind and ultrasound-guided injection techniques for the dorsal retrobulbar nerve block in horses. Methods: Equine cadaver heads were used to inject the retrobulbar space with contrast medium (CM). Injections were performed either blindly based on anatomic landmarks (blind group, n = 44) or under ultrasonographic guidance (US-group, n = 44), equally divided between an experienced and unexperienced operator. Needle position and distribution of CM were assessed with computed tomography imaging and evaluated by a board-certified veterinary diagnostic imager blinded to the technique. Safety and accuracy of both techniques were compared.Results: Ocular penetration was observed in two cases (n = 2/44) in the blind group but not in the US group (n = 0/44). No intrathecal, intraneural, or intravascular injections were seen in either group. Safety was significantly improved in the US group (p = .026). There was no statistically significant difference between the groups regarding the accuracy of the injection. Excellent accuracy was achieved more often with the ultrasound-guided technique (n = 11/22) than with the blind technique (n = 7/22) when performed by the unexperienced operator, but this difference was not statistically significant. Conclusion:To prevent globe-threatening complications and improve the safety of the injection, we recommend using the ultrasound-guided injection technique for the dorsal retrobulbar nerve block.