Acid‐base imbalances and the association of blood‐gas variables, electrolytes, and biochemical analytes with outcome in hospitalized calves undergoing abdominal surgery

Abstract

Abstract Background Surgical abdominal emergencies in calves are associated with a guarded prognosis and have the potential for complex metabolic derangements including acid‐base imbalances. Objectives To perform a comprehensive analysis of acid‐base status and to assess the prognostic relevance of preoperative clinicopathologic variables in calves undergoing abdominal surgery. Animals Hospital‐based study samples of 535 (dataset 1; DS1) and 83 calves (dataset 2; DS2). Methods Retrospective (DS1) and prospective (DS2) case series. Results In DS1, acidemia (pH 7.37) was present in 30.7% of calves. Plasma L‐lactate, chloride, and serum inorganic phosphorus concentration accounted for 51.9%, 11.6% and 9.4% of the variation of venous blood pH, respectively. Classification tree analysis indicated that a negative outcome (death or euthanasia during hospitalization) was associated with venous pO2 ≤33.6 mm Hg, anion gap >18.3 and >22.9 mEq/L, serum albumin concentration ≤36.5 and ≤29.4 g/L, serum urea concentration >4.4 mmol/L, and plasma ionized calcium concentration ≤1.26 mmol/L. The area under the receiver operating characteristic curve of this model was 0.85 (95% CI: 0.82‐0.89, P < .001) and the resulting sensitivity and specificity for the prediction of nonsurvival at the optimal probability cut‐point of 0.5 was 89.8% and 65.7%, respectively. In DS2 the model had a similar sensitivity and specificity of 90.5% and 70%, respectively. Conclusions and Clinical Importance Clinicopathologic imbalances and associated changes of acid‐base status are common in calves with surgical abdominal emergencies and have clinical utility for the prediction of a negative postoperative outcome.

Keywords

• acidemia
• gastrointestinal ileus
• peritonitis
• prognosis
• venous oxygen tension