Influence of flow rate, fluid temperature, and extension line on Hotline and S-line heating capability: an in vitro study

Abstract

Background A fluid warmer can prevent hypothermia during the perioperative period. This study evaluated the heating capabilities of Hotline and Barkey S-line under different flow rates and initial fluid temperatures, as well as after the extension line installation.

Methods We measured the temperature of a 0.9% sodium chloride solution at the fluid warmer outlet (TProx) andthe extension line end (TDistal) with three different initial fluid temperatures (room, warm, and cold)and two flow rates (250 ml/hr and 100 mL/hr).

Results At a 250 ml/hr flow rate, the TProx and TDistal values were observed to be higher in Hotline than in S-linewhen using room-temperature or cold fluid. Administering of the warm fluid at the same flow ratesignificantly increased the TProx and TDistal values in S-line more than the cold and room-temperaturefluids. At flow rates of 100 ml/hr, TDistal values were significantly lower than TProx values in bothdevices regardless of the initial fluid temperature.

Conclusions Hotline outperformed S-line for warming fluids at a high flow rate with cold or room-temperaturefluids. Administering warm fluid in S-line prevented a decrease in the fluid temperature at a high flowrate. However, at a low flow rate, the fluid temperature significantly decreased in both devices afterpassing through an extension line.