Energy metabolism of infants and children with systemic inflammatory response syndrome and sepsis

Objective To evaluate whether critically ill children with systemic inflamm atory response syndrome (SIRS) or sepsis have altered resting energy expend iture (REE) and substrate utilization. Summary Background Data Studies in adults with sepsis have shown increased energy expenditure and mobilization of endogenous fat. In infants and child ren, energy metabolism and substrate utilization during sepsis have not bee n characterized. Methods Metabolic studies were performed in 21 critically ill children with SIRS or sepsis. Twenty-one stable control children, matched for weight, we re also studied. Seven patients required inotropic support and 17 received mechanical ventilation. Fifteen patients with SIRS had evidence of bacteria l, fungal, or viral infection and were considered septic. Respiratory gas e xchange was measured by computerized indirect calorimetry for 1 to 2 hours continuously. Results The REE of patients with SIRS or sepsis was not different from that of controls. Similarly, there were no differences in carbon dioxide produc tion and oxygen consumption. Resting energy metabolism was not different be tween patients with SIRS and patients with sepsis. In addition, the presenc e of low platelet count or inotropic support did not affect resting energy metabolism. The median respiratory quotient of patients with SIRS or sepsis was 0.88 (range 0.75-1.12), indicating mixed utilization of fat and carboh ydrate; this was not significantly different from that of controls. The Ped iatric Risk of Mortality Score was not significantly correlated with REE or respiratory quotient. Conclusions The energy requirements of children with SIRS or sepsis are not increased. Their resting metabolism is based on both carbohydrate and fat utilization. The authors speculate that these children divert the energy fo r growth into recovery processes.