2009 Southern Regional Meeting Abstracts

Purpose of Study: To calculate the theoretical incidence of lead (PB) or mercury (Hg) toxicity due to blood transfusions in extremely low birth weight (ELBW) infants.
Methods Used: Extremely low birth weight (ELBW) infants, birth weight of ≤1000g, were evaluated for the number of PRBC transfusions they received during their entire hospitalization. A weekly theoretical Pb load received during the first week of life was calculated based on the following assumptions: 1)30% of all PRBC transfusions given during the entire hospitalization (N) are given during the first week of life, 2)Pb content in PRBC is 3.5 times that of whole blood, 3)10 ml/kg as the volume of PRBC given per transfusion, and 4)Pb or Hg content in the whole blood of an adult blood donor is the same as that of the average general population (H). Hence 0.3 * N PRBC transfusions per hospitalization*10 ml blood/kg *3.5 * H mcg/dl= mcg/kg/week Pb load given during the first week of life. This Pb dose was then compared to the provisional tolerable weekly intake (PTWI) dose set by the WHO. For Hg, we calculated a load given with each PRBC transfusion. Hg content in PRBC is twice that of whole blood. We also assumed that Hg levels in childbearing-age women reflect average general population Hg levels. So for Hg load estimation the formula is 10ml blood/kg*2*H mcg/L= mcg/kg/transfusion. This calculated load was compared to current daily oral Reference Dose (RfD) set by the US Environmental Protection Agency.
Summary of Results: In the years 2005 and 2006, there were 258 patients with a birth weight of ≤1000g. All received one or more PRBC transfusions. There were a total of 2122 transfusions from 208 PRBC units. The minimum number of transfusions from a single PRBC unit was 5. Based on the outlined formula, there were 50 infants (19%) who potentially received a toxic Pb dose based on the average general population whole blood Pb level of 1.64 mcg/dl. Based on a prevalence Hg level ≥ 6.04 mcg/L in 5% in women of childbearing-age, a minimum of 52 blood transfusion procedures gave a Hg load above the RfD.
Conclusions: Pb and Hg toxicity in ELBW infants as a result of blood transfusions may be common. There is a need to evaluate the true incidence of this possible toxicity by testing PRBC units for Pb and Hg content before being cleared for transfusion in ELBW infants.