Insensible Water Loss during the First Week of Life of Extremely Low Birth Weight Infants Less than 25 Gestational Weeks under High Humidification

Abstract

Purpose: Extremely-low-birth-weight infants (ELBWIs), especially those ≤24 gestational weeks (GW), presented extremes in IWL and changes of water balance. The purpose of the present study was to retrospectively investigate fluid and electrolyte balance in infants of ≤24-GW during the first postnatal week under high humidification. Methods: Medical records of extremely-low-birth-weight infants (ELBWIs) who were born and admitted to the Neonatal Intensive Care Unit at Samsung Medical Center during March 2004–September 2010 were reviewed. Fluid intake, urine output, insensible water loss (IWL) and electrolyte balance of 22-GW (n=14), 23-GW (n=40) and 24-GW (n=67) infants nursed in high humidity (95%) were compared with ≥26GW (n=65) infants nursed in 60% humidity Results: Survival rate until discharge was 33%, 82%, 75% and 89.3% in 22-GW, 23GW, 24-GW and ≥26-GW infants, respectively. Compared to ≥26-GW infants, fluid intake and IWL was higher in 22-GW and 23-WG, but not as different in 24-GW. At postnatal day (P) 3–5, urine output was significantly lower in ≥26-GW infants than in the other age groups. Serum sodium level was significantly higher in 22-, 23- and 24GW (P1–2) than in ≥26-GW infants. Hypernatremia (150 mEq/dl sodium) was more frequent in 22-GW (71%), 23-GW (41%) and 24-GW (21%) than in ≥26-GW infants (14%). Conclusion: High-humidity environments significantly decreased fluid intake and improved electrolyte imbalance in 24-GW, but not in 22- and 23-GW infants. Increased IWL in the latter might be related to more immature skin, implicating the need for additional nurturing conditions.