The recent TCCC guidelines TCCC guidelines for the management of hypothermia in tactical combat casualty care conclude that the use of IV fluid/blood-warming devices is an essential component for managing hypothermia caused by either penetrating, blunt, or burn trauma and should deliver consistent output temperatures at 38° (100°F) but no higher than 42°C (108°F) at a flow rate of up to 150mL/min and perform to standard within the extremes of military environments.
The guidelines also state that currently available, FDA-approved portable infusion fluid warming devices vary significantly in regard to ideal device specifications (e.g., weight, size, cost, flow rates, output fluid temperature). Therefore, the guidelines recommend that selected devices should be tested to ensure that desired performance characteristics are met.
There are 3 important takeaways regarding active warming devices that can be derived from the guidelines:
1. The Warrior outperforms traditional warmers:
The TCCC Guidelines state that in a recent study, Lehavi et al. evaluated the following four in-line, battery-operated fluid warmers that were developed for use in the prehospital environment: Belmont Buddy Lite™ (Belmont Medical Technologies), enFlow™ (Vyaire Medical), Thermal Angel™ (Estill Medical Technologies), and QinFlow Warrior™. Using normal saline, they studied three warming device characteristics: (1) heating performance over time, (2) the volume that can be effectively heated, and (3) the flow resistance. The authors reported that the performance characteristics of these fluid warmers varied with flow and initial input temperatures. They studied two input fluid temperatures, 10°C and 20°C, and two fluid flow rates, 50 and 200mL/min. Among the portable fluid warmers evaluated in the Lehavi et al. study, the Warrior™ provided the best warming performance at high infusion rates and low input temperatures (i.e., average output temperatures were 37.8°C [100°F] at 50mL/min; 36.1°C (97°F) at 100mL/min; and 34.4°C (94°F) (at 200mL/min). Only the enFlow™ and Warrior™ functioned reliably in accordance with the manufacturer’s specifications. The Buddy Lite™ was limited to moderate input temperature and low flow rates, and the Thermal Angel™ was limited by battery capacity to low fluid volumes and low output temperature in cold environmental conditions.
2. Although the Quantum™ device was developed to military prehospital specifications, it does not meet the key ideal performance characteristics for use on the battlefield:
The guidelines mention the recently-introduce Quantum™ device (Life Warmer). As can be inferred from the guidelines, although this device was developed to military prehospital specifications, it does not meet the ideal performance characteristics for use on the battlefield. These specifications require the warming of 4 units of whole blood at 150ml/min. According to the manufacturer, this device is limited to 2 units of blood and 100 ml/min (50% and 66% of the ideal performance spec, respectively).
3. Aluminum fluid path is potentially toxic!
The guidelines alert users regarding solutions that include aluminum since aluminum may be toxic. Recent research on the enFlow™ warmer device show elevated aluminum level in IV fluid after it passes through the uncoated aluminum heating plate in this device. No other [FDA cleared] portable warming device has a similar warming-plate system with aluminum contacting blood.
Press HERE to read the full TCCC guidelines.