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October 24, 2005
9:00:00 AM - 11:00:00 AM
Hall C4
Relative Efficacy of Hotline, Buddy and Ranger Blood/Fluid Warming Devices
Christopher V. Maani, M.D., Paul D. Mongan, M.D.
Department of Anesthesiology, Uniformed Services University, Bethesda, Maryland, United States
INTRODUCTION: Intraoperative hypothermia is easier to prevent than to reverse. Fluids administered at a high rate need fluid warming devices to prevent temperature decreases that result from infusions at or below room temperature. We evaluated the Hotline (SIMS Level 1, Inc., Rockland, MA), Ranger (Arizant Healthcare, Eden Prairie, MN) and Buddy (Belmont Instrument Corp., Billerica, MA) warming devices in regards to their warming efficacy at various flow rates and temperatures, with and without varying degrees of infusion pressure.

METHODS: Each device was set up in accordance with the manufacturer specifications using the device-specific infusion set. Room temperature [20-21°C] crystalloid [0.9% normal saline] and colloid [Hextend], as well as 10°C packed red blood cells were infused through each warming system over a series of flow rates. These fluids were also infused with no pressure (gravity flow) or varying levels of pressure on the infusion bag (150 and 300 mmHg). Simultaneous outflow temperatures were recorded via an inline thermistor attached to the distal end of the IV tubing/infusion set as an estimate of the clinical endpoint; the warmed fluid actually delivered to the patient.

RESULTS: While all three devices were able to warm crystalloids equally at flow rates of 3 liters/min or less; the Hotline was significantly less capable at flows of 6 lpm or greater. The Buddy was unable to match the Ranger's ability at flows of 9 lpm or greater. Likewise, all three devices were able to warm crystalloid, colloid and PRBC's at gravity flow; however, the Hotline was unable to maintain warming capacity at infusion pressures of 150 mm Hg or greater for crystalloid. The Hotline could not maintain warming capacity for colloid or PRBC's at infusion pressures of 300 mm Hg. Flow rates at all infusion pressures were comparable for all devices (»6 lpm flow). While there was a statistically slight decrease (p>0.05) in the ability of the Buddy to warm PRBCs and Hespan at infusion pressures of 300 mm Hg, the average 1.5°C difference may not be clinically significant.

DISCUSSION: The prevention of intraoperative hypothermia is associated with improved postoperative outcomes. While the routine use of fluid warmers is not indicated for low flow infusions, fluid warming for cold fluids at high flow rates can prevent intraoperative hypothermia. In this evaluation the Ranger and Buddy devices performance was significantly better than the Hotline. One advantage of the Buddy design is that the heating element is a portable extension of the main component and the disposable is very low volume. One advantage of this design is the ease of transportability of the heating element and the disposable so active fluid warming can be easily continued from the operating room to the postoperative period. These differences could translate into clinical differences in practice.

CONCLUSION: Based on our blood/fluid warming data, the Ranger and Buddy are recommended warming device; especially for PRBCs and colloids at high infusion pressures.[figure1]

Anesthesiology 2005; 103: A856
Figure 1