Objective To determine the prognostic significance of plasma lactate concentration, plasma lactate clearance, and delta lactate in dogs and cats presented to an emergency room (ER). Design Retrospective study. Setting University teaching hospital. Animals A total of 8,321 animals with a plasma lactate concentration measured with 4,863 presenting to the ER and 1,529 dogs and 444 cats having a measurement within 4 hours of admission. Interventions None. Measurements and main results Plasma lactate concentration of dogs and cats presented to a university teaching hospital was retrospectively evaluated. Of dogs and cats with a plasma lactate concentration measured within 4 hours of admission to the ER, hyperlactatemia was common, and the prevalence of hyperlactatemia for dogs 78% (361/462) and cats 67% (78/116) was highest when evaluated within the first 30 minutes following admission. The distribution of patient's plasma lactate concentration was significantly higher in non‐survivors compared to survivors at all time points evaluated (P0.28em<0.28em$\; < \;$0.001). Both lactate clearance (P = 0.010) and delta lactate (P = 0.013) were significantly different between survivors and nonsurvivors. A delta lactate > 4.5 mmol/L was 100% (95% CI: 95 to 100%) specific for nonsurvival in patients with hyperlactatemia measured within 1 hour of admission to the ER. The most common cause of hyperlactatemia was shock in dogs (24%) and urinary tract diseases in cats (22%). Shock was associated with the highest mortality rate in both dogs (61%) and cats (77%). Hyperlactatemia was significantly associated with increased mortality for dogs with shock (P = 0.001), respiratory diseases (P = 0.022), diabetes mellitus (P = 0.018), and liver dysfunction (P = 0.006). Conclusions Hyperlactatemia was associated with mortality in both dogs and cats when measured at any time point in the 4 hours following admission to the ER. Serial lactate measurement may also be a valuable tool to guide clinical management decisions.

Objective To describe patient characteristics, underlying disease processes, clinical outcomes, transfusion dose and type (therapeutic or prophylactic), platelet count changes, and adverse events associated with platelet concentrate (PC) administration in dogs. Design Retrospective study. Setting University teaching hospital. Animals A total of 149 dogs, representing 189 PC transfusion episodes. Interventions None. Measurements and Main Results In this population, 39 of 149 dogs (26.2%) were diagnosed with primary immune‐mediated thrombocytopenia, 22 of 149 (14.8%) had decreased bone marrow production, 12 of 149 (8.0%) received PC during a massive transfusion, 3 of 149 (2.0%) had congenital thrombocytopathia, 59 of 149 (39.6%) had severe thrombocytopenia of other causes, and 14 of 149 (9.4%) underwent transfusion for miscellaneous causes without a documented severe thrombocytopenia. In 117 of 149 dogs (78.5%), >1 site of hemorrhage was noted. The most common sites of hemorrhage were the gastrointestinal (GI) tract in 89 of 149 (59.7%) and the skin in 78 of 149 (52.3%). Overall survival to discharge was 59.1% (88/149). The median PC dose was 0.8 units per 10 kg of body weight per transfusion episode (range: 0.2–6.7). Of 189 episodes, 29 of 189 (15.7%) were prophylactic, and 158 of 189 (83.6%) were therapeutic. For 99 of 189 transfusion episodes, paired pre‐ and postplatelet counts were available within 24 hours. The median platelet count change was 5.0 × 109/L (5000/μL; range: –115 × 109/L to 158 × 109/L [–115,000 to 158,000/μL]); the posttransfusion platelet count was significantly higher than pretransfusion (P < 0.0001). The increase in platelet count after transfusion was greater in the prophylactic group than the therapeutic group (P = 0.0167). Transfusion reactions were suspected during 2 of 168 episodes (1.2%). Conclusions Immune‐mediated thrombocytopenia was the most common disease process that resulted in PC transfusion. PC was more frequently administered to animals with active hemorrhage rather than prophylactically, and most dogs had evidence of hemorrhage in multiple organ systems, particularly the GI tract and skin. PC transfusions typically appeared safe, and the median platelet count increased after transfusion.

A 7-y-old male Labrador Retriever dog was presented because of acute onset of dark-colored urine after a hunting session the day prior. Moderate hemoglobinemia was observed, associated with transient hemoglobinuria and hematuria with no concurrent evidence of underlying urinary tract disease. The patient’s clinical signs resolved within 36 h post-exercise without specific treatment. The concurrent occurrence of exertional hemolysis and hematuria in a dog is uncommon; these conditions are commonly reported separately in human athletes.