Factors influencing the outcome of equine anaesthesia: a review of 1,314 cases

Patient data, physiological variables and recovery quality were extracted from 1,314 records of equine anaesthetics covering a 7-year period and analysed retrospectively. Better recovery quality was significantly associated with shorter duration of anaesthesia, longer recovery times, less invasive surgery, a lower pulse rate at induction and higher pulse and respiratory rates during anaesthesia. Nineteen animals suffered serious anaesthetic-related problems (1.4% incidence) and 9 died (0.68% incidence). Clinical treatment of hypotension during anaesthesia significantly reduced the hypotensive index but did not significantly alter the recovery quality or incidence of post-anaesthetic myopathy. The severity of the myopathy was, however, markedly reduced in the animals treated for hypotension.