Impaired fat utilization in parenterally fed low-birth-weight infants suffering from sepsis.

Lipid infusion in low-birth-weight infants suffering from sepsis is still controversial. Consequently, we investigated the fat tolerance in six low-birth-weight infants with sepsis and 15 low-birth-weight infants without sepsis. For measurement of fat clearance, we assayed the serum concentrations of triglycerides enzymatically, and of the free fatty acids by colorimetric micromethod. The fatty acid oxidation was analyzed with the [13C]triolein breath test by means of ratio-mass spectrometry. The infants were maintained on continuous parenteral nutrition with various amounts of soybean oil emulsion (1 g, 2 g, and 3 g fat/kg body weight per day). Comparing the lipid infusion of 1 and 2 g fat/kg body weight per day between the two groups, we found triglyceride and free fatty acid values in both groups to be in the normal range. At a dose of 3 g of fat/kg body weight per day, septic low-birth-weight infants showed a significantly higher concentration of triglycerides (2.02 +/- 0.46 mmol/liter) and of free fatty acids (2.06 +/- 0.45 mmol/liter) than the nonseptic low-birth-weight infants (triglycerides: 1.09 +/- 0.43 mmol/liter; free fatty acids: 1.05 +/- 0.41 mmol/liter). The low-birth-weight infants with sepsis showed a reduced fat oxidation rate of 16.0 +/- 1.5% in contrast to that of the low-birth-weight infants without sepsis, whose rate was 38.4 +/- 1.8%. Accordingly, we apply dosages not exceeding 2 g of fat/kg body weight per day to septic low-birth-weight infants.