POSTOPERATIVE CHANGES IN RESTING ENERGY-EXPENDITURE AND INTERLEUKIN-6LEVEL IN INFANTS

The relationship was determined between resting energy expenditure (RE E) and interleukin (IL)6 level following surgery in infants. Sixteen i nfants of mean(s.e.m.) weight 3.2(0.2) kg undergoing uncomplicated sur gery were studied. The operative stress score was recorded and plasma IL-6 levels were measured before and 4, 8, 12 and 24 h after surgery. Respiratory gas exchange was measured by indirect calorimetry before a nd at 2, 4, 6, 8, 10, 12, 24 and 48 h. Urinary nitrogen excretion was measured and calculated. IL-6 levels increased significantly after sur gery (P=0.006) and were maximal at 12 h. There was a linear correlatio n between the increase in IL-6 level and operative severity score (r=0 .61, P=0.012). REE increased significantly after operation (P<0.001), peaking at 2-4 h, and returned to baseline levels by 12 h. The changes in REE preceded those in IL-6. IL-6 is a marker of the stress respons e in infants and may play a role in the subsequent modulation of this response.