# Effect of Ice Consistency and Sodium Chloride Additives on Cooling Speed and Final Temperature for Cold Water–Ice Immersion in Heat Stroke

## TL;DR

This study shows that using crushed ice, cold water, and salt can cool water faster and to lower temperatures, which may help treat heat stroke more effectively.

## Contribution

The study introduces a novel method for optimizing cold water-ice mixtures by evaluating the effects of ice type, salt, and water temperature.

## Key findings

- Crushed ice with salt achieved the fastest and lowest cooling temperatures.
- Cubed ice in warm water cooled more slowly compared to other mixtures.
- All mixtures reached equilibrium after 300 seconds, but with significant temperature differences.

## Abstract

Heat stroke can rapidly progress to end organ damage and death if not promptly treated. The diagnosis is characterized by core body temperature > 40.5 °C. In this study we evaluate how the form of ice (crushed vs cubed), the addition of sodium chloride, and the initial temperature of water together affect the rate of cooling for standardized cooling bath mixtures used to treat patients experiencing heat stroke.

We prepared four cold water immersion mixtures using 12 quarts of ice and 12 quarts of water (11.36 liters) under different conditions:
Test Case 1: Cubed ice with trauma bay tap water (~35 °C);Test Case 2: Crushed ice with cold tap water (~24 °C);Test Case 3: Crushed ice with cold tap water plus four pounds of rock salt;Test Case 4: Cubed ice with cold tap water,

Test Case 1: Cubed ice with trauma bay tap water (~35 °C);

Test Case 2: Crushed ice with cold tap water (~24 °C);

Test Case 3: Crushed ice with cold tap water plus four pounds of rock salt;

Test Case 4: Cubed ice with cold tap water,

After each mixture was poured into a 40-quart bucket and mixed thoroughly, we recorded the temperature at 20-second intervals over a total duration of 300 seconds using a food-grade thermometer. Room temperature during the experiment was 25.0 °C.

After 100 seconds, water from the trauma bay with cubed ice reached 6.2 °C, while cold tap water with cubed ice cooled to a slightly lower temperature of 5.5 °C. Crushed ice in cold tap water reached an even lower temperature of 3.6 °C. The coldest mixture was made with crushed ice with salt, which rapidly reduced the water temperature to 2.2 °C. It took approximately 300 seconds for all test groups to approach equilibrium, with final temperatures of 2.4. °C for cubed ice in trauma bay water, 1.4 °C for cubed ice in cold tap water, 1.2 °C for crushed ice in cold tap water, and 0.2 °C for crushed ice with salt in cold tap water.

A mixture of cold tap water, crushed ice, and sodium chloride achieved a lower equilibrium temperature and cooled more rapidly than mixtures lacking salt, using cubed ice, or prepared with warmer initial water temperature. These findings suggest that optimizing cold water immersion protocols with crushed ice, added salt, and the coolest available tap water may enhance cooling speed in simulated mixtures. Whether these differences translate into improved patient outcomes remains to be determined.