Alarming Levels of Carboxyhemoglobin in Banked Blood

Objective: To determine the level of carboxyhemoglobin found in banked blood in the Albany, NY region.

Design: A retrospective descriptive analysis of carboxyhemoglobin (COHb) levels in a series of packed red blood cell (PRBC) units.

Setting: The blood bank of a university tertiary care hospital in Albany, NY.

Participants: All PRBC units considered for possible use in pediatric cardiac surgery were first analyzed for levels of COHb.

Interventions: Only those units with COHb levels of <1.5% were deemed acceptable for use during pediatric cardiac surgery.

Results: A sample of blood drawn from the sample side arm of each PRBC unit was analyzed on a Chiron 855 Blood Gas Analyzer (Chiron Inc, Emeryville, CA, now Siemens/Bayer RapidLab 865) to determine the level of COHb. The average COHb level was 0.78% (standard deviation +/- 1.48%), and out of the 468 units tested, 48 (10.3%) had COHb levels of 1.5% or greater. The highest recorded COHb level was 12%.

Conclusions: The transfusion of PRBC units may artificially elevate readings of COHb and cause confusion over possible causes. Certain high-risk populations (eg, cyanotic neonates undergoing cardiopulmonary bypass) may be especially at risk. Although levels of COHb in the US blood supply are dropping, institutions may want to consider analyzing COHb levels in their PRBC units before transfusion in these high-risk populations.