Immediate effects of alkaline infusion in infants with respiratory distress syndrome

Nineteen infants with acidosis associated with RDS were studied following the infusion of: (1) 0.58M (7%) THAM over 30 seconds; (2) molar bicarbonate over 30 seconds; (3) molar bicarbonate over 2 minutes; and (4) molar bicarbonate over 5 minutes. PaC02 fell after THAM; PaC02 rose sharply after bicarbonate and remained elevated 10 minutes after infusion. The pH rose abruptly in all infants and remained significantly elevated 10 minutes after infusion. Pa02 changes were variable; no infant had immediate improvement in Pa02. The changes in osmolality, hematocrit, and colloid osmotic pressure describe the immediate osmotic hemodilution following the infusion of hypertonic base.