Transient pelvic limb neuropathy following proximal metatarsal and tarsal magnetic resonance imaging in seven horses.

BACKGROUND: Pelvic limb neuropathy is a rare post-anaesthetic complication. In the authors' experiences, the incidence of post-anaesthesia neuropathy is increased following MRI of the proximal metatarsus and tarsal regions when compared with previously reported incidences of post-anaesthetic neuropathy. OBJECTIVES: This study reports the incidence, diagnosis, treatment and outcome of seven horses with post-anaesthesia neuropathy following proximal metatarsal and tarsal MRI. STUDY DESIGN: Retrospective case series. METHODS: Case record review of horses receiving general anaesthesia for MRI between 1 January 2012 and 31 December 2017. RESULTS: A total of 1134 MRI procedures were performed and reviewed for analysis. Eight cases of neuropathy were identified in 1088 limb scans (0.74%). Of these cases, one was subsequent to thoracic limb imaging (1/834; 0.12%) and seven were subsequent to imaging of proximal metatarsal and/or tarsal structures (7/181; 3.9%). Following proximal metatarsal and/or tarsal MRI, transient nondependent limb femoral neuropathy developed in six of the seven affected horses, with one additional horse developing peroneal neuropathy of the dependent limb. Recovery of pelvic limb function occurred within 72 h and 9 days in six and one horse, respectively. MAIN LIMITATIONS: Anaesthetic protocol and neuropathy treatment for the affected horses were not standardised. CONCLUSIONS: Though an uncommon complication in horses, transient neuropathy may occur more frequently following MRI of the proximal metatarsal and tarsal structures when compared with other MRI scans. This may be due to patient positioning and the requirement for limb traction for MRI of more proximal regions. Supportive care facilitates rapid return to function.

The clinical effects of a low dose dexmedetomidine constant rate infusion in isoflurane anesthetized cats.

The aim of this study was to evaluate the effects of a low dose dexmedetomidine constant rate infusion (CRI) on cardiopulmonary function, inhalant anesthetic concentration and recovery in isoflurane anesthetized cats. In a prospective, randomized, blinded, controlled design, 12 cats undergoing anesthesia for ovariohysterectomy were administered hydromorphone (0.1mg/kg) intramuscularly, propofol (4.3-7.8mg/kg) intravenously and maintained with isoflurane. During isoflurane anesthesia, the cats were administered either a dexmedetomidine loading dose (0.5µg/kg) followed by a dexmedetomidine CRI (0.5µg/kg/h) (group LDD), or a saline loading dose followed by a saline CRI (group SAL). Heart rate (HR), respiratory rate, blood pressure, temperature, oxygen saturation (SpO2), end tidal carbon dioxide concentration (ETCO2), end tidal isoflurane concentration (ETISO) and anesthetic depth were recorded at nine time points (T0-T8). Overall effects (T1-8) and individual time point results were compared between groups. There were no significant differences in baseline variables (T0), age, weight, propofol dose, anesthesia and surgery time, time to extubation or recovery score between groups. Among the physiological variables measured, significant differences were observed in respiratory rate, ETCO2, and mean and diastolic blood pressure, between groups at individual time points. Systolic blood pressure, HR, SpO2, ETISO and temperature were not significantly different between groups at individual time points. Overall, ETCO2 and ETISO were significantly lower and respiratory rate was significantly higher for LDD compared to SAL. At the doses administered, a CRI of dexmedetomidine reduced isoflurane requirements in anesthetized cats undergoing ovariohysterectomy. The utility of a low dose dexmedetomidine CRI in the perioperative setting requires further investigation, since intraoperative cardiopulmonary values during dexmedetomidine infusion were not different from those receiving saline.

The lack of analgesic use (oligoanalgesia) in small animal practice.

Oligoanalgesia is defined as failure to provide analgesia in patients with acute pain. Treatment of pain in emergencies, critical care and perioperatively may influence patient outcomes: the harmful practice of withholding analgesics occurs in teaching hospitals and private practices and results in severe physiological consequences. This article discusses the prevalence, primary causes, species and regional differences and ways to avoid oligoanalgesia in small animal practice. Oligoanalgesia may be addressed by improving education on pain management in the veterinary curriculum, providing continuing education to veterinarians and implementing pain scales.