[Hotline 2: heating capabilities of a coaxial fluid warming system at low and moderate flow rates].
OBJECTIVE
The aim of this study was to compare the effects of two coaxial fluid warming systems with their heating capabilities.


METHODS
The heating capabilities of two coaxial fluid warming systems and their capabilities to warm fluids at 20 +/- 0.5 degrees C (20 degrees C room temperature) was measured: 1) Hotline 1 Fluid Warmer, 2) Hotline(R) 1 Fluid Warmer. Final temperatures were measured at different infusion rates (10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 400, 800, 1000 ml/h and at maximal flow rates (Vmax)), at the distal end of the disposable tubing. Statistical analysis was performed using a computer based program (NCSS). Differences between the groups were analysed using the Two-Way-ANOVA. Significance was defined at a p < 0.05.


RESULTS
At flow rates between 10 - 1000 ml/h, infusion temperatures of > 36 degrees C were attained by both devices in a reliable manner. Compared to Hotline 1, Hotline 2 attained higher final temperatures of between 1.2 - 3.8 % (p < 0.01). Hotline 1 was measured to have higher Vmax (+ 3.6 %) compared to Hotline 2 (p < 0.01). However, the mean final temperature at Vmax of Hotline 2 was increased by 6.5 % (p < 0.01). The time needed to warm target temperature to 40 - 41 degrees C took between 9 to 12 minutes (flow rate 10 ml/h and Vmax respectively) when using Hotline 1 and 3 to 4 minutes when using Hotline 2.


CONCLUSIONS
Compared to its predecessor, the Hotline 2 performance is a valuable improvement with respect to heating capacity and clinical handling.
Schnoor
J
J
Klinik für Anästhesiologie, Universitätsklinikum Aachen. joerg.schnoor@gmx.de
Macko
S
S
Weber
I
I
Rossaint
R
R
D007035:Hypothermia; D007700:Kinetics; D017694:Rewarming / Q000295:instrumentation*; D013696:Temperature; D013816:Thermodynamics