Retrospective Evaluation of Acid-Base Disorders in Dogs With Hyperlactatemia Using Traditional and Semiquantitative Analysis: 3866 Cases.

OBJECTIVE

To characterize acid-base disorders in dogs with hyperlactatemia via traditional and semiquantitative approaches, and to investigate the mechanisms of hyperlactatemia and the prognostic significance of metabolic acidosis in these patients.

DESIGN

Retrospective study.

SETTING

University teaching hospital.

ANIMALS: A total of 3866 dogs with various diseases and a plasma lactate concentration >2 mmol/L at any timepoint during hospitalization underwent traditional acid-base analysis. Among these patients, 1755 dogs had data available for semiquantitative acid-base evaluation.

MEASUREMENTS AND MAIN

RESULTS

The most common disease associated with hyperlactatemia was gastrointestinal disorders in 1232 of 3866 dogs (29.3%), and the most common mechanism of hyperlactatemia was circulatory shock in 741 (19.1%). The traditional approach identified acid-base abnormalities in 2586 dogs (66.9%), with the most common being primary respiratory acidosis in 609 (15.7%). When considering both primary and mixed disorders, metabolic acidosis was present in 1452 patients (37.5%). When excluding the lactate effect, the semiquantitative approach identified concurrent acidifying and alkalinizing effects in 1241 of 1755 dogs (70.7%). Unmeasured anions, determined via semiquantitative analysis, were the most frequent acidifying effect in 775 dogs (44.1%). Metabolic acidosis, whether primary or as part of a mixed disorder, was associated with increased mortality (682/1452 [46.9%]) compared with patients without metabolic acidosis (479/2414 [19.8%]) (p < 0.001). Similarly, type A hyperlactatemia was associated with higher mortality (374/717 [52.5%]) than type B (227/746 [30.4%]) (p < 0.001).

CONCLUSIONS

Acid-base disorders in dogs with hyperlactatemia were frequent and complex, with both acidifying and alkalizing processes often occurring simultaneously. The semiquantitative approach might be a valuable tool to improve our understanding of the underlying mechanisms of metabolic acid-base disorders in these patients. The presence of metabolic acidosis was most frequent in dogs with type A hyperlactatemia and was associated with higher mortality.