Evaluation of commercially available fluid-warming devices for use in forward surgical and combat areas

The fluid-warming capabilities of four individual fluid warmers, i.e., Level 1, FMS 2000, Thermal Angel, and Ranger, were compared to evaluate their potential for medical use in forward military echelons of care. Lactated Ringer's solution (LR) and Hextend at room temperature (20 degrees C) or refrigerated temperature (4-7 degrees C) and packed red blood cells at 4 degrees C to 7 degrees C were used with each warmer at two different flow rates. The FMS 2000 consistently warmed all fluids to approximately 37 degrees C, regardless of the starting temperature or flow rate. The Level 1 and Ranger also efficiently warmed all fluids except cold LR to approximately 37 degrees C. The Thermal Angel generally warmed room temperature fluid, cold Hextend, and packed red blood cells to at least 33 degrees C to 34 degrees C but could not warm cold LR. The clinical standard is to have fluids warmed to 32 degrees C at a minimum and more preferably to 34 degrees C to 35 degrees C. Of the fluid warmers tested, only the Thermal Angel failed to achieve such a temperature in warming cold LR. Data from the present study suggest the Ranger and FMS 2000 to be operationally adaptable to at least echelons 1 and 2, respectively, whereas far-forward use of the Thermal Angel has limitations.