Heparin and Prematurity

The use of certain heparin sodium injections and heparin lock flush solutions is considered by the manufacturers to be contraindicated in premature infants and infants of low birth weight. Some formulations of these drugs contain benzyl alcohol which, in bacteriostatic saline intravascular flush and endotracheal tube lavage solutions, has been associated with fatalities and severe respiratory and metabolic complications in low-birthweight premature infants. Symptoms include a striking onset of gasping respiration, hypotension, bradycardia, and cardiovascular collapse. The manufacturers further recommend that use of these products be avoided in all neonates whenever possible. Neonates requiring heparin lock flush solution should be given a preservative-free formulation. Nevertheless, many experts feel that, in the absence of benzyl alcohol-free equivalents, the amount of the preservative present in these formulations should not necessarily preclude their use if they are clearly indicated. The American Academy of Pediatrics considers benzyl alcohol in low doses (such as when used as a preservative in some medications) to be safe for newborns.

The use of heparin for maintaining patency of umbilical artery catheters may be associated with an increased risk of germinal matrix intraventricular hemorrhage in low-birthweight neonates. Although a definitive causal relationship has not been established, caution may be appropriate when heparin lock flush solutions are used.

Due to the risk of overdose, heparin lock flush solutions containing 100 units/mL should not be used in neonates, particularly those who are premature or have low birthweight.