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

Abstract 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.