Renal bicarbonate handling in low birth weight infants during metabolic acidosis.
We studied the fractional excretion of bicarbonate (FE HCO-3) in 10 low birth weight infants aged 1-6 days during metabolic acidosis (base excess greater than or equal to -5 mEq/l) and during subsequent sodium HCO-3 infusion. The mean birth weight was 1,095 g; the mean gestational age was 29 weeks. The ability to decrease urine pH to less than 5.5 and FE HCO-3 to less than 1% during metabolic acidosis was not limited by low gestational age or birth weight. After HCO-3 therapy, all infants corrected their negative base excess, and plasma HCO-3 increased significantly. All infants with blood pH less than or equal to 7.22 or PaCO2 greater than or equal to 50 mm Hg had minimal or absent FE HCO-3. Infants with elevated PaCO2 and mild or absent acidosis also had complete HCO-3 tubular reabsorption. These results suggest that the HCO-3 tubular reabsorption is adequate during metabolic and/or respiratory acidosis in low birth weight infants.
D000138:Acidosis / Q000097:blood / Q000188:drug therapy / Q000652:urine*; D001639:Bicarbonates / Q000097:blood / Q000627:therapeutic use / Q000652:urine*; D001769:Blood; D002245:Carbon Dioxide / Q000097:blood; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007668:Kidney / Q000378:metabolism*; D008297:Male; D012964:Sodium / Q000627:therapeutic use; D017693:Sodium Bicarbonate; D014556:Urine
D001639:Bicarbonates; D002245:Carbon Dioxide; D017693:Sodium Bicarbonate; D012964:Sodium