Comparison of the brainstem auditory evoked responses during sevoflurane or alfaxalone anaesthesia in adult cats.

OBJECTIVE: To compare the effects of general anaesthesia using sevoflurane or alfaxalone on the brainstem auditory evoked response (BAER) test in adult healthy cats. STUDY DESIGN: Prospective, clinical, 'blinded', crossover study. ANIMALS: Ten feral adult healthy cats. METHODS: Premedication consisted of dexmedetomidine (0.01 mg kg-1) intramuscularly (IM). The first general anaesthesia was induced and maintained with sevoflurane (treatment S) for physical examination, BAER test, complete blood tests, thoracic radiographs and abdominal ultrasound. The second general anaesthesia was induced with alfaxalone (treatment A) IM (2 mg kg-1) and maintained with alfaxalone (10 mg kg-1 hour-1) for the BAER test, followed by neutering surgery. The BAER recordings were compared for differences in latencies, amplitudes and waveform morphology. Data were analysed using Student's t test and Wilcoxon rank test for paired samples for parametric and non-parametric data, respectively. Statistical significance was set at p < 0.05. RESULTS: General anaesthesia was uneventful; normal BAER comprising five peaks could be identified in both treatments. Mean ± SD latencies were 1.05 ± 0.09, 1.83 ± 0.11, 2.52 ± 0.19, 3.43 ± 0.17 and 4.39 ± 0.15 ms and 1.03 ± 0.04, 1.81 ± 0.73, 2.53 ± 0.15, 3.37 ± 0.13 and 4.33 ± 0.13 ms in treatments S and A, respectively. Median (interquartile range) amplitudes were 2.83 (0.67), 1.27 (0.41), 0.30 (0.40), 1.05 (0.82), 0.61 (0.38) microvolts and 2.84 (1.21), 1.49 (1.18), 0.26 (0.32), 0.91 (0.50) and 0.92 (0.64) microvolts in treatments S and A, respectively. There were no statistically significant differences in mean latencies or median amplitudes between both the anaesthetics. CONCLUSIONS AND CLINICAL RELEVANCE: This study demonstrates that there were no statistically significant differences between both the anaesthetics on the BAER test in adult healthy cats. Moreover, two possible anaesthetic protocols are described for cats undergoing this electrodiagnostic test.

Retrospective study of the perioperative management and complications of ureteral obstruction in 37 cats.

OBJECTIVES: To describe perioperative management and complications, risk factors and mortality rates in cats anaesthetized for treatment of ureteral obstruction. STUDY DESIGN: Retrospective, clinical, cohort study. ANIMALS: Thirty-seven client-owned cats anaesthetized for ureteral surgery. METHODS: Records with sufficient data for cats treated between March 2010 and March 2013 were examined for breed, age, gender, history, concurrent diseases, pre- and post-anaesthetic biochemical and haematological parameters, American Society of Anesthesiologists classification, anaesthetic protocol, surgical technique, surgeon, perioperative complications and mortality within 48 hours after extubation. Associations between risk factors and outcome variables were evaluated using univariable analysis. Odds ratios and 95% confidence intervals were calculated for significant parameters. Sensitivity and specificity using receiving operator characteristic curve analysis were calculated for creatinine, potassium level and standard base excess (SBE) to denote survival or non-survival. RESULTS: Preoperatively, all cats were azotaemic: mean±SD urea was 31.6 ± 26.9 mmol L(-1) and median (range) creatinine was 562 µmol L(-1) (95 µmol L(-1) to off scale). Thirteen cats were hyperkalaemic (K+ 6.5 mmol L(-1)). Anaesthesia-related complications included bradycardia (n=8, 21.6%), hypotension (n=15, 40.5%) and hypothermia (n=32, 86.5%). Seven cats (18.9%) died postoperatively. Non-survivors were significantly (p=0.011) older (9.8±1.9 years) than survivors (6.4±3.1 years) and had higher potassium concentrations (p=0.040). Risk factors associated with mortality were ASA classes IV and V (p=0.022), emergency procedures (p=0.045) and bicarbonate administration (p=0.002). Non-survivors had higher creatinine concentrations (p=0.021) and lower SBE (p=0.030). CONCLUSION AND CLINICAL RELEVANCE: Intraoperative anaesthetic complications were common; increased age, poor health status, preoperative bicarbonate administration, hyperkalaemia and increased creatinine were associated with increased risk for death and can be used to predict risk for complications.

Clinical signs, causes, and outcome of central cord syndrome in 22 cats.

OBJECTIVE: To describe the signalment, clinical findings, presumptive or definitive diagnosis, and outcome in cats with central cord syndrome (CCS). ANIMALS: 22 cats. CLINICAL PRESENTATION: Cats evaluated for CCS at 7 referral hospitals between 2017 and 2021 were included. Information retrieved from medical records included signalment, physical and neurological examination findings, diagnostic investigations, definitive or presumptive diagnosis, treatment, and follow-up. RESULTS: Median age at presentation was 9 years. Two neuroanatomical localizations were associated with CCS: C1-C5 spinal cord segments in 17 (77.3%) cats and C6-T2 spinal cord segments in 5 (22.7%) cats. Neuroanatomical localization did not correlate with lesion location on MRI in 8 (36.3%) cats. The most common lesion location within the vertebral column was over the C2 and C4 vertebral bodies in 6 (27.2%) and 5 (22.7%) cats, respectively. Peracute clinical signs were observed in 11 (50%) cats, acute in 1 (4.5%), subacute in 4 (18%), and chronic and progressive signs were seen in 6 (40.9%) cats. The most common peracute condition was ischemic myelopathy in 8 (36.3%) cats, whereas neoplasia was the most frequently identified chronic etiology occurring in 5 (22.7%) cats. Outcome was poor in 13 (59%) cats, consisting of 4 of 11 (36.6%) of the peracute cases, 3 of 4 (75%) of the subacute cases, and 6 of 6 of the chronic cases. CLINICAL RELEVANCE: Central cord syndrome can occur in cats with lesions in the C1-C5 and C6-T2 spinal cord segments. Multiple etiologies can cause CCS, most commonly, ischemic myelopathy and neoplasia. Prognosis depends on the etiology and onset of clinical signs.