Evaluation of a New Fluid Warmer Effective at Low to Moderate Flow Rates

Abstract

The tendency of intravenous fluid exiting the heat exchanger of a fluid warmer to cool to room temperature increases as the rate of infusion slows and the length of tubing between the heat exchanger and the patient increases. Thus, slow to moderate flow rates result in the delivery of fluid near room temperature despite the use of a fluid warmer. The volumes infused even at low flow rates may be large relative to the size of infants and children and may result in a significant decrease in patient temperature. A new warmer (Hotline, Level 1 Technologies) that actively heats the fluid in the delivery tubing was evaluated and compared to two different conventional dry-wall warmers: the model DW1000A (Baxter Health Care) and the FloTem IIe (DataChem). Cold blood (4-10 degrees C) and room temperature saline (22 degrees C) were pumped through the warmers and the delivered temperature was measured as the flow rate was varied from 50 to 12,000 ml/h. The Hotline was more effective than the Baxter or the FloTem IIe at flow rates between 50 and 6,000 ml/h for saline and at flow rates between 50 and 3,000 ml/h for blood. Insulating the tubing beyond the heat exchangers of the conventional warmers improved their performance, but the delivered temperatures were still less than those of the Hotline at low flow rates. The Hotline is more effective than conventional warmers at slow flow rates, and may be useful for preventing hypothermia when large volumes of fluid relative to patient size are infused at slow rates.