Prospective evaluation of plasma lactate parameters for prognosticating dogs with shock.

Objective: To determine whether admission venous plasma lactate concentration, serially calculated lactate variables, or the Acute Patient Physiologic and Laboratory Evaluation (APPLE ) score could discriminate hospital survivors from non-survivors in dogs presenting to the emergency department with clinical signs of shock.

Design: Prospective case series performed over a 24-month period.

Setting: Large urban private teaching hospital.

Animals: Seventy-one dogs admitted to the ICU with initial peripheral venous plasma lactate concentration > 2.5 mmol/L and clinical and hemodynamic parameters consistent with shock.

Interventions: None.

Measurements And Main Results: Heart rate, systolic blood pressure, temperature, initial venous plasma lactate, and APPLE score were recorded at admission. Lactate concentrations were serially recorded at predefined time points and used to calculate lactate variables, including lactime (time lactate > 2.5 mmol/L), lactate clearance ([lactate - lactate ]/ lactate × 100), and LAC (area under the lactate concentration versus time curve). Primary outcome was survival to discharge. Overall survival rate was 61%. Admission plasma lactate did not differ between groups (P = 0.28). Lactime was shorter in survivors vs non-survivors (P = 0.03). Lactate clearance at hours (h) 1, 4, 10, and 16 was greater in survivors vs non-survivors (P < 0.05). Final plasma lactate clearance differed between groups (P < 0.05). LAC at time intervals 1 to 4 hours, 4 to 10 hours, 10 to 16 hours, and 16 to 24 hours was larger in non-survivors vs survivors (P < 0.05). Total LAC did not differ between groups (P = 0.51). Admission APPLE was not different between survivors and non-survivors (P = 0.16).

Conclusions: While neither single APPLE nor admission plasma lactate concentration could discriminate between hospital survivors and non-survivors, measures of lactate clearance can prognosticate survival in dogs with shock.