Simulated clinical evaluation of four fluid warming devices*

The fluid warming capabilities of the Bair Hugger, Hotline, Standard Ranger and Fluido devices were evaluated in the laboratory with gravity flow via a 14G cannula (1 m head of fluid) and with the fluid bag pressurised to 300 mmHg. The resulting flows (70-450 ml.min(-1)) were recorded. At a room temperature of 22 degrees C, no device warmed the fluid to 37 degrees C. However, the Standard Ranger with gravity flow and the Fluido with both gravity and pressurised flow achieved 35 degrees C, whereas the Bair Hugger and Hotline with both gravity and pressurised flow, and the Standard Ranger with pressurised flow, achieved only 24-31 degrees C. However, from the way delivered temperatures changed with flow, we calculated that all four devices would achieve close to 37 degrees C at the flows specified by the manufacturers: 17, 83, 150 and 800 ml.min(-1) for the Bair Hugger, Hotline, Standard Ranger and Fluido, respectively.