Performance Characteristics of High Efficiency Fluid and Blood Warmer using Print Circuit Board Heater at Various Flow Rates

Background: Currently available warming devices are often heavy and cumbersome, requiring development of more portable, user friendly, high efficiency fluid and blood warmer. The intravenous fluid heating capabilities of a new, heat-plate print circuit board (PCB) based warmer at various low flow rates were tested. Methods: Model Joyother BM-1® was investigated for normal saline (0.9% NaCl) and colloid at various infusion rates (60-6000 ml/hr). Final temperatures were measured by electronic thermometer after passing through the warmer. Effective warming was defined as a fluid temperature ≥ 32℃. Ambient temperature was maintained at 22-25℃. Degree of heating capability and temperature decrease were compared and correlated between different flow rates. Results: The device warmed the room temperature crystalloid and colloid efficiently. Its warming capability was continuously improved as the flow rates increased in all tested flow rates, reaching maximum 41℃. After the warming, the temperature decrease showed high negative correlation with the flow rates. The extent of cooling was less in colloid. No overheating was noted at sudden brake. Conclusions: Joyother BM-1® heated crystalloid and colloid sufficiently and safely enough for clinical application (exit temperature ≥ 35℃) at various flow rates. The warming capacity and the length of the intravenous tube infusion system determined the efficiency of the warmer. Further study is warranted for the efficiency of warming for the blood and its element changes. (Korean J Anesthesiol 2006; 51: 598~605)