Prognosis in equine colic: a comparative study of variables used to assess individual cases.

The present retrospective study compared objectively the prognostic value of many variables routinely used in the assessment of equine colic cases. The best prognostic variables were those which assessed the integrity of cardiovascular function. Ranked in order of decreasing merit the following variables were able to discriminate between horses which lived and those which died: systolic pressure, blood lactate concentration, oral mucous membrane capillary refill time, diastolic pressure, arterial pulse amplitude, degree of mental depression, blood urea concentration, haematocrit, heart rate, haematocrit/plasma protein ratio, oral mucous membrane colour, jugular filling rate, frequency of gut sounds, differential blood leucocyte count, blood glucose concentration and respiratory rate. Assessment of systolic pressure alone appropriately classified the outcome (survival or death) of 86 per cent (64 out of 73) cases examined. Combined assessment of systolic pressure, blood lactate concentration, blood urea concentration and haematocrit permitted accurate classification of 93 per cent (68 of 73) of the cases examined. Outcome classification formulae for these four variables, alone and in all combinations, are presented.