# A Proof-of-Concept for a Continuous-Temperature Circulating Water Bath in Frostbite Limb Rewarming

## TL;DR

A new water bath system was tested to consistently rewarm frostbitten limbs, showing better results than traditional methods.

## Contribution

A continuous-temperature circulating water bath was developed and tested for effective frostbite rewarming.

## Key findings

- Pig feet warmed more effectively in water maintained at 39.0°C using the Anova Precision Cooker NANO.
- The system achieved consistent tissue rewarming without requiring constant monitoring.
- The final tissue temperature reached 36.7°C with the system versus 34.2°C without it.

## Abstract

Frostbite is a thermal tissue injury that can occur following prolonged exposure to freezing temperatures, often resulting in tissue ischemia and sometimes requiring amputation. The American Burn Association recommends rapid rewarming of frostbite injuries in 38–42 °C water for 15–30 minutes, but clinical application of this recommendation is often inconsistent. Our objective was to find a method to better facilitate frostbite treatment by creating a continuous-temperature circulating water bath and demonstrating its effectiveness with a proof-of-concept, descriptive study. We hypothesized that this design would effectively rewarm chilled extremities within 30 minutes without healthcare workers being required to continually monitor and maintain water temperature. We constructed a continuous-temperature circulating water bath system using a reservoir and an Anova Precision Cooker NANO. Pig feet were chilled and then immersed in 39.0 °C water with or without the Anova Precision Cooker NANO. Without the Anova Precision Cooker NANO, tissue warmed from 3.2 ± 0.3 °C to 34.2 ± 0.2 °C over 30 minutes (final water temperature of 36.5 ± 0.1 °C). With it, tissue warmed from 2.7 ± 0.2 °C to 36.7 ± 0.2 °C (final water temperature of 39.1 ± 0.1 °C). The continuous-temperature circulating water bath offers a standardized, reliable, and effective method for rewarming hypothermic tissue. Our approach could provide a solution to inconsistent and impractical frostbite rewarming methods in clinical settings to better promote rewarming compliance. Further studies are ongoing to validate the feasibility of using the continuous-temperature circulating water bath in clinical practice.