Field Warming of IV Fluids

Abstract

Several studies have been performed examining the use of heat packs from Meals Ready to Eat (MRE) to warm IV fluids. All have attempted to heat the fluid while it was still in the bag. In one study, that resulted in a delay of between 13 and 19 minutes in reaching the desired temperature. In a second study, there was a delay of 10 minutes, but only 500 mL of fluid was heated. The purpose of this study was to determine the feasibility of using MRE heat packs to adequately warm a bolus infusion of cold IV normal saline. The heat packs from 2 MREs were placed inside 1 plastic bag. The heat packs were activated with the recommended volume of water (time 0). Two sets of coils were made in 254-cm long IV tubing. Each set consisted of four 5-cm diameter coils held with duct tape. Both coils were placed between the activated heat packs in the plastic bag. A bolus infusion was simulated by running 5°C NS through the line with an 18G IV catheter. Fluid supply and infusion temperatures were recorded every second with thermocouples inside the fluid bag and inside the end of the IV tubing. Ambient temperature was 3°C. The IV fluid supply temperature was 5°C during the entire infusion. Simulated infusion temperature reached 35°C an average of 4.2 minutes after beginning setup. Average peak infusion temperature was 46.3°C. This method of heating IV fluids with MRE heat packs can effectively raise infusion temperature to the recommended levels within 5 minutes. This method is independent of supply bag volume and reduces heat loss in transit as heating occurs in the tubing.