We studied the fractional excretion of bicarbonate (FE HCO3-) in 10 low birth weight infants aged 1-6 days during metabolic acidosis (base excess ≥ -5 mEq/1) and during subsequent sodium HCO3- infusion. The mean birth weight was 1,095 g; the mean gestational age was 29 weeks. The ability to decrease urine pH to >5.5 and FE HCO3- to >1% during metabolic acidosis was not limited by low gestational age or birth weight. After HCO3- therapy, all infants corrected their negative base excess, and plasma HCO3- increased significantly. All infants with blood pH ≥7.22 or PaCO2 ≥ 50 mm Hg had minimal or absent FE HCO3-. Infants with elevated PaCO2 and mild or absent acidosis also had complete HCO3- tubular reabsorption. These results suggest that the HCO3- tubular reabsorption is adequate during metabolic and/or respiratory acidosis in low birth weight infants.
- Low birth weight infants
- Urine bicarbonate
ASJC Scopus subject areas
- Pediatrics, Perinatology, and Child Health
- Developmental Biology