Active warming of saline or blood is ineffective when standard infusion tubing is used: an experimental study

Abstract

Purpose: To determine the effect of infusion rate, tubing length and fluid composition on the temperature of the infusate reaching the distal end of an infusion tubing with and without active fluid warming.Methods: Warmed normal saline (W-NS) and packed red blood cells (W-PRBC), were infused with a fluid warmer through a modified infusion set. The fluids were delivered at eight infusion rates from 50 to 999 mL·hr -1 . The infusate temperature was monitored at 20 cm intervals on the iv tubing. The same temperature monitoring protocol was applied to PRBC without warmer (NoW-PRBC).Results: In W-NS and W-PRBC groups, there was a decrease in the infusate temperature, at each flow rate, from the drip chamber to the distal end of tubing ( P <0.001). In NoW-PRBC group, there was a rapid increase in the infusate temperature from the bag to the drip chamber ( P <0.001). Thereafter, there was no change in temperature, except at the 999 mL·hr -1 infusion rate, where a slight increase in the infusate temperature throughout the tubing was shown. In W-NS and W-PRBC groups increasing the flow rate produced a significant increase in the infusate temperature, at each measurement point ( P <0.001). In the NoW-PRBC group, increasing the flow rate did not alter the infusate temperature. The fluid composition did not influence the infusate temperature.Conclusion: There is an important heat exchange within the tubing, which is aggravated at low flow rates. At infusion rates appropriate for pediatric anesthesia the clinical and economic value of fluid warming without the use of heated extension tubing is questionable.Objectif : Déterminer l'effet de la vitesse de perfusion, de la longueur de la tubulure et de la composition du liquide sur la température de la solution intraveineuse à la partie distale de la tubulure, le liquide étant soumis ou non à un réchauffement actif. Méthode : Une solution salée (SS-R) et un concentré de globules rouges réchauffés (CGR-R) ont été perfusés avec un ensemble à perfusion modifié comprenant un réchauffeur de liquide. Les liquides ont été administrés selon huit vitesses de perfusion, de 50 à 999 mL·h -1 . La température du soluté a été mesurée à des intervalles de 20 cm sur la tubulure iv. Le même protocole de surveillance de la tempéra-ture a été appliqué au CGR non réchauffé (CGR-NonR). Résultats : Dans les groupes SS-R et CGR-R, la température du liquide perfusé a baissé pour toutes les vitesses de perfusion, entre la chambre compte-gouttes et la partie distale de la tubulure (P < 0,001). Dans le groupe CGR-NonR, elle a augmenté rapidement, entre le sac et la chambre compte-gouttes (P < 0,001). Par la suite, il n'y a pas eu

A laboratory comparison of the performance of the buddy lite™ and enFlow™ fluid warmers

“…The enFlow device is capable of warming both room temperature-and cooled fluid at all the flow rates tested, making it a more flexible device for the operating theatre setting. Tubing length has a profound influence on the fluid temperature entering the patient [5,8]. Doublewalled infusion lines with coaxial flow around the infusate maintain the warming effect along the length of the tubing.…”

Evaluation of the Performance and Safety of a Newly Developed Intravenous Fluid Warmer

“…Heating using a blood warmer results in hemolysis. Heat loss along the intravenous line is a serious problem in the use of heated fluids (11)(12)(13).…”

The laboratory performance of the enFLOW®, buddy lite™and ThermoSens®fluid warmers

“…Studies have suggested that fluid warmers are usually unnecessary in adults below a flow of 35 ml.min À1 , which reduces the core body temperature by less 0.5°C, although the effect depends upon body mass [6,8]. Infusate heat loss increases with the length of the intravenous line [10,11,[15][16][17]. Short lines can be used with the warmers we studied as they are small and can be positioned close to the patient.…”

“…Infusate heat loss increases with the length of the intravenous line [10,11,[15][16][17]. Short lines can be used with the warmers we studied as they are small and can be positioned close to the patient.…”