Energy expenditure of critically ill neonatal foals

Reasons for performing study: Nutritional support in critically ill neonatal foals is of great importance given their high metabolic rate and minimal stores of energy and protein. Nutrient requirements of healthy growing foals have been estimated based on daily milk intake; however, little is known about the resting energy expenditure (REE) of sick foals. Objectives: To determine REE in critically ill neonatal foals (sepsis and/or hypoxic-ischaemic encephalopathy [HIE] and compare this with REE in control foals. Methods: Critically ill newborn foals admitted to the Fundació Hospital Clinic Veterinari, Universitat Autònoma de Barcelona, Spain from March 2009 to February 2011 were included in this study. Healthy neonatal foals and foals with nonsystemic conditions were used as controls. Oxygen consumption and CO2 production were measured with a respiratory monitor connected to a tight fitting facemask and REE (kcal/kg bwt/day) was calculated with the abbreviated Weir formula. Measurements were performed within 24 h of admission and repeatedly during hospitalisation. Results: Twenty-seven foals were included (16 critically ill foals and 11 controls) and a total of 47 measurements were performed. In the critically ill, REE was reduced (mean +/- s.e. 49.5 +/- 2.1 kcal/kg bwt/day) on admission relative to the controls. In surviving foals (n = 5), REE before hospital discharge was not different (68.4 +/- 7.0 kcal/kg bwt/day) from control foals (64.8 +/- 2.7 kcal/kg bwt/day). Conclusions: REE was lower in critically ill foals upon admission (40-50 kcal/kg bwt/day) and normalised before hospital discharge (60-80 kcal/kg bwt/day). Potential relevance: Critically ill neonatal foals tolerating enteral feeding would receive approximately their REE when given 10% of their bodyweight in mare's milk daily. For sick neonates unable to tolerate enteral nutrition, provision of 50 kcal/kg bwt/day would be a reasonable goal for parenteral nutrition