Effect of sepsis syndrome on neonatal oxygen consumption and energy expenditure

Objective. To evaluate oxygen consumption (VO2), carbon dioxide production, and energy expenditure (EE) in full-term neonates with early-onset neonatal septicemia daily for 7 days beginning at the day of clinical diagnosis of sepsis. Methods. A total of 17 spontaneously breathing fullterm neonates, 10 with clinical signs of sepsis and 7 healthy neonates (control group), were enrolled in the study. Age at first study day was 3 +/- 0.9 days in both groups. Sepsis syndrome was defined as a systemic response to a bacterial infection with clinical signs of infection, elevated values of interleukins 6 and 8 and C-reactive protein, and abnormal white blood cell count and positive blood cultures (9 group B streptococci, I Escherichia coli). Measurements of VO2 and carbon dioxide production were performed daily for 7 days by means of indirect calorimetry. Results. In the septic infants, VO2 and EE were increased by about 20% at days 1 to 3 and by 15% at day 4 when compared with the controls. From days I to 3, EE averaged 57 +/- 3 kcal/kg/d in the septic neonates and 47 +/- 2 kcal/kg/d in the controls. At day 4, EE was 55 +/- 2 and 47 +/- 2 kcal/kg/d, respectively. Energy intake was about the same in both groups, whereas weight gain during the 7 study days was significantly lower in the sick patients than in the control group (19 +/- 2 g/d vs 33 +/- 9 g/d and 5.4 +/- 0.5 g/kg/d vs 9.4 +/- 2.6 g/kg/d, respectively). Increased EE was associated with increased heart rate (126 +/- 4 vs 112 +/- 4 min(-1) at day 1) and respiratory rate (56 +/- 6 vs 40 +/- 4 min(-1) at day 1). There were no differences in rectal temperature (37.3 +/- 0.4degreesC vs 37.4 +/- 0.2degreesC), skin temperature (36.5 +/- 0.4degreesC vs 36.6 +/- 0.3degreesC), and oxygen saturation (96 +/- 3% vs 96 +/- 3%) between the 2 groups. Conclusions. Neonates with sepsis syndrome have elevated VO2 and EE values that could explain impaired growth during the illness period and may make the infants vulnerable to insufficient calorie supply during the acute phase of septic disease.