Microwave Oven vs Level-1 Rapid Fluid Warmer: A Comparative Efficacy Study of Fluid Warming in the ATLS Protocol (MOLEWA Study)

Objective: Although the use of a microwave for fluid warming has been proposed, standardized protocols for its clinical application remain limited. The purpose of this study is to evaluate the effectiveness of microwave-based fluid warming compared to conventional fluid warming equipment. Materials and Methods: This in-vitro experimental study was conducted in two phases. In the pilot trial, we compared five groups using different combinations of container types, infusion rates, and warming techniques. In the second phase, a non-inferiority trial, two groups of 18 1-liter isotonic crystalloid bottles were compared: one using the Level-1 H-1200 fluid warmer and the other employing a microwave oven warming protocol (800W, two minutes at maximum power). The primary outcome was the percentage of infusion time during which the fluid temperature at the tip of the infusion set remained within the target range of 37°C to 42°C. Results: The warming cabinet and microwave oven achieved mean infusion durations of 5.0 and 19.5 minutes, respectively. The Level-1 group maintained the target temperature for 100% of the infusion duration, while the microwave group achieved a rate of 95.84% [95.82%-95.86%], demonstrating non-inferiority to the Level-1 method. Conclusion: Microwave fluid warming is a feasible, practical, and cost-effective alternative to conventional fluid warming equipment. Its comparable warming efficiency and wide availability support its potential use in rural areas with limited resources.