VITAMIN-A STATUS AND AIRWAY INFECTION IN MECHANICALLY VENTILATED VERY-LOW-BIRTH-WEIGHT NEONATES

Vitamin A (retinol) plays an important role in immunity. Respiratory and enteral infections in children are associated with low serum vitamin A concentrations that improve during recovery. To test the hypothesis that airway infection in very-low-birth-weight (VLBW) neonates likewise may be associated with a change in vitamin A status, we examined 20 VLBW neonates (selection criteria: birth weight 700-1300 g, gestational age 26-30 weeks, need for supplemental oxygen and mechanical ventilation for >72 hr after birth) who were enrolled in the control group of a randomized clinical trial of vitamin A supplementation reported earlier. We studied changes in weekly measurements of plasma concentrations of vitamin A and retinol-binding protein (REP) during 4 weeks following enrollment in the trial (postnatal day 4) and compared changes between periods with and without airway infections. Seventeen infants had 22 episodes of documented airway infection. Staphylococcus epidermidis was the predominant organism. Plasma vitamin A concentrations decreased during 19 out of 22. With airway infection (mean change: -4.1 to -18.6 mu g/dL), while they increased during 37 out of 58 periods without airway infection (mean change: -0.2 to +5.8 mu g/dl; P < 0.001). The mean (+/-SD) plasma vitamin A concentrations before, during, 1 week after, and 2 weeks after an episode of airway infection were 20.9 +/- 8.3, 9.7 +/- 4.1, 12.8 +/- 8.9, and 16.2 +/- 7.2 mu g/dL, respectively. The mean value during airway infection was significantly lower than those before and two weeks after airway infection (P < 0.05). All of the individual plasma vitamin A concentrations during airway infection were low (<20.0 mu g/dL). Airway infection had no significant effect on plasma REP concentrations. We conclude that airway infection in mechanically ventilated VLBW neonates is associated with low plasma vitamin A concentrations that improve during recovery. We speculate that the depletion of marginal liver stores of vitamin A from its increased tissue utilization during airway infection may account for this change in the vitamin A status. Further studies are needed to establish the cause and effect relationship between vitamin A deficiency and airway infection in these infants. (C) 1995 Wiley-Liss. Inc.