Oxygen consumption and resting energy expenditure during phototherapy in full term and preterm newborn infants.

OBJECTIVES To determine the effect of phototherapy on the oxygen consumption and resting energy expenditure of term and preterm newborn infants. METHODS A total of 202 infants (gestation 30-42 weeks; body weight 1270-4100 g) requiring phototherapy for the treatment of neonatal hyperbilirubinaemia were enrolled in a randomised crossover study. In random sequence, the oxygen consumption and resting energy expenditure were measured twice in each infant by indirect calorimetry, once at the end of six hours of continuous phototherapy and once after a control period of at least six hours without phototherapy. Anterior abdominal wall temperature was servocontrolled at 36.5 degrees C throughout the study. RESULTS At the end of six hours of continuous phototherapy, oxygen consumption (mean (SD): 6.21 (1.35) v 6.26 (1.51) ml/kg, p = 0.555) and resting energy expenditure (178.11 (37.62) v 180.37 (43.14) kJ/kg/24 h, p = 0.382) did not differ significantly from those measured after the control period. There were also no significant differences in heart rate, respiratory rate, or rectal temperature. Subgroup analysis of those of gestation < 37 weeks or < 34 weeks also showed no effect of phototherapy on either oxygen consumption or resting energy expenditure. CONCLUSION Phototherapy has no effect on the metabolic rate of thermally stable term or preterm infants.