Evaluation of a new high-efficiency blood warmer for children

Abstract

Because currently available blood warmers are inadequate for infants and children requiring massive transfusion, the performance of a new high-efficiency pediatric blood warmer (System 250(TM), LEVEL 1® Technologies Inc., Marshfield, Massachusetts) was evaluated and compared with a commonly used conventional blood warmer (Model DW1000A, American Pharmaseal, Valencia, California). Cold (5-6°C), diluted red blood cells (RBC) (Hct = 30%) were infused through the warmers over a series of flow rates, and the resulting temperatures of the infusate were measured. The flow rates of diluted packed RBC were also measured over a series of infusion pressures. At a flow rate of 225 ml/min, the output temperature of the System 250(TM) was 33.6°C compared with 24.6° C (P < 0.05) for the conventional warmer. Above a flow rate of 250 ml/min, however, the water bath of the System 250(TM) cooled significantly, resulting in a deterioration of performance and an output temperature of only 24.2°C at a flow rate of 400 ml/min. With a 16-G catheter attached, the flow rate at a pressure of 300 mmHg was 223 ml/min through the System 250(TM) compared with 160 ml/min (P < 0.05) for the conventional warmer. The System 250(TM) produced higher output temperatures and a lower resistance to flow compared with the conventional warmer, but flow rates of cold blood through the System 250(TM) should be restricted to 250 ml/min or less to ensure adequate warming.