Relations of Nosological Factors and Energy Expenditure in Newborns

Abstract

Purpose. With the aid of indirect calorimetry, to evaluate whether the nosological factors affect energy exchange in severely ill newborns.

Materials and methods. Indirect calorimetry was employed to determine the true energy expenditure in new borns under the mechanical ventilation because of intranatal postanoxia encephalopathy (n=19), severe sepsis (n=18), and urgent surgery (n=19). Energy expenditure at rest was estimated at the beginning of intensive therapy and in in 48 hours. Sedation in groups was similar.

Results. At the first stage, the energy exchange in all newborns was characterized by hypometabolism. In cases of damage of the central nervous system the anaerobic metabolism was increased, and the principal used substrate was glucose; the most prolonged hypometabolism was revealed in newborns with sepsis, in which the utilization of lactate was decreased, and the main energetic substrate were lipids; in early postoperative period, the decrease in energy expenditure was not associated with preferential oxidation of glucose or lipids, and disappeared due to elimination of anesthetics.

Conclusion. Energetic hypometabolism can be considered as a main reaction of the newborn organism to previous invasion. Acute posthypoxic brain damage in newborns is characterized by high activity of peroxidation associated with hypometabolism. For newborns with severe sepsis a slow recovery of aerobic metabolism and intensity of energy expenditure were evident. Early postoperative period in newborns was characterized by profound iatrogenic hypometabolism with fast normalization of energy expenditure.