Alterations in carbohydrate metabolism in critically ill cats

Objective: To characterize the alterations in carbohydrate metabolism as they relate to the development of hyperglycemia in critically ill cats. Design: Prospective, observational, controlled study. Setting: Intensive care unit at a university veterinary teaching hospital. Animals: Twenty-six non-diabetic cats admitted into the intensive care unit for a variety of diseases and 21 healthy control cats. Interventions: Blood samples were obtained from critically ill cats upon admission to the intensive care unit. Blood was similarly obtained from control cats. Measurements and main results: For all cats, venous blood glucose, lactate, cortisol, insulin, glucagon, epinephrine, norepinephrine, and non-esterified fatty acid concentrations were determined and compared between the 2 groups of cats. Compared with controls, critically ill cats had significantly higher median concentrations of glucose [183 (range 51-321) mg/dL versus 110 (91-165) mg/dL; P < 0.001], lactate [2.5 (0.6-11.1) mmol/L versus 1.8 (0.4-4.1) mmol/L; P=0.01], cortisol [7.8 (0.3-53.7) mu g/dL versus 4.4 (1.5-8.3) mu g/dL; P=0.005], glucagon [186 (46-3128) pg/mL versus 97 (30-252) pg/mL; P=0.001], and norepinephrine [1.5 (0.2-16.4) pg/mL versus 0.63 (0.21-3.61) pg/mL; P=0.003]. Compared with controls, critically ill cats also had a significantly lower median plasma insulin concentration [9 (2-52) mu U/mL versus 17 (3-35) mu U/mL; P=0.04]. The presence or degree of hyperglycemia in critically ill cats was not related to any single measured variable. Conclusions: Similar to critically ill human patients, alterations in carbohydrate metabolism are present in critically ill cats and likely contribute to the hyperglycemia commonly observed in this population.