Association of blood lactate concentration with physical perfusion variables, blood pressure, and outcome for cats treated at an emergency service

OBJECTIVE: To determine the association of blood lactate concentration with physically assessed perfusion variables, systolic arterial blood pressure (SAP), and outcome in cats evaluated by an emergency service. DESIGN: Prospective, observational study. ANIMALS: 111 cats. PROCEDURES: Initial blood lactate concentration and SAP (prior to any therapeutic interventions) as well as physically assessed perfusion variables (mucous membrane color, capillary refill time, peripheral pulse quality, heart rate, and rectal temperature) were determined. Cats were categorized as having no shock, mild to moderate shock, or severe shock. Outcomes were recorded. Associations between lactate concentration and these variables were assessed. RESULTS: Median initial blood lactate concentration was 2.7 mmol/L (range, 0.5 to 19.3 mmol/L); cats with white mucous membranes, abnormal peripheral pulse quality, and hypothermia had significantly higher lactate concentration than did cats without these findings. Median lactate concentration for cats with SAP < 90 mm Hg (3.3 mmol/L) was significantly higher than that of cats with SAP ≥ 90 mm Hg (2.35 mmol/L). Cats with severe shock had significantly higher lactate concentration (4.3 mmol/L) than did cats in other shock categories. Median initial lactate concentration at admission did not differ between cats that did (2.45 mmol/L) and did not (3.2 mmol/L) survive to discharge from the hospital. Change in lactate concentration during hospitalization (when applicable) was not associated with outcome. CONCLUSIONS AND CLINICAL RELEVANCE: Findings indicated that blood lactate concentration, together with physical examination findings and SAP, may be a useful tool for identifying abnormalities in tissue oxygen delivery in cats. However, lactate concentrations were not associated with outcome in the present study.