Retrospective analysis of selected predictors of mortality within a veterinary intensive care unit

The records of 204 cats entering the intensive care unit (ICU) at the University of Edinburgh Small Animal Hospital between December 2002 and October 2006 were retrospectively analysed. Of these, 37 cats over 12 months of age had a systolic blood pressure recorded on entry into the ICU, and this group comprised our study population. Of these 37 cats, 36 had both heart rate and respiratory rate recorded on entry into the ICU, whilst 24 of these cats also had body temperature recorded. The relationship between (i) survival to discharge and (ii) survival until 21 days after admission to the ICU was analysed using univariate generalised linear models with binomial errors. The robustness of any significant relationship was assessed using multivariate analysis methods. In addition, receiver operator curves (ROC) were generated for any of the significant predictors of mortality and from these curves the threshold values, optimal sensitivity and specificity were calculated. Using these values survival curves were generated for any significant prognostic indexes. A decreased blood pressure at the time of admission to the ICU was found to be a significant negative predictor of survival until discharge from the hospital. Overall, a systolic blood pressure of 124 mmHg or higher at the time of admission to the ICU has a sensitivity of 47.8% and a specificity of 85.7% for predicting that a cat will survive until discharge from the hospital.