Lan Chen,1,* Chang Liu,1,* Zhaocai Zhang,2 Yuping Zhang,1 Xiuqin Feng1 

1Nursing Department, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310009, People’s Republic of China; 2Department of Critical Care Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310009, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Xiuqin Feng, Nursing Department, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, 310009, People’s Republic of China, Tel +8613757119151, Email fengxiuqin@zju.edu.cn

Background: Rapid core temperature reduction is crucial for treating heatstroke. Clinical methods like cooling blankets and cold fluid infusions are common, but their specific effects are not well defined. This study evaluates these methods’ cooling effects and prognosis impact in classic heatstroke rats.
Methods: Sixty Sprague Dawley rats with classic heatstroke were divided into five groups: cooling blanket, cold fluid infusion, combination (combined cooling blanket and cold fluid infusion), natural cooling (control), and cold water immersion (positive control). Core temperature and mean arterial pressure were monitored. Blood samples were taken at 0.5 and 2 hours post-cooling for analysis. Half the rats underwent pathological evaluation and apoptosis analysis of heart and kidney tissues at 2 hours. The rest were observed for 24-hour survival.
Results: The combination group showed the fastest cooling within 10 minutes. Cooling blanket and cold fluid infusion groups had similar cooling rates. Heart and kidney function indicators and inflammatory cytokine levels were significantly lower in the combination and cold fluid infusion groups compared to the cooling blanket group. Pathological damage was highest in the cooling blanket group. Cooling rate negative correlated with organ function indicates and inflammation markers. No rats in the cooling groups died, while seven in the natural cooling group did.
Conclusion: Cooling methods differ in effectiveness and impact on inflammation and organ function. While cooling blankets demonstrate limited therapeutic efficacy and potential risks when used in isolation, rapid cold fluid infusion emerges as the preferred cooling modality by preserving cardiac structure and renal function while attenuating systemic inflammation. Early rapid cooling improves organ function and prognosis in classic heatstroke rats. Proper cooling methods are crucial for effective heatstroke management, reducing organ damage, and improving survival rates.Plain language summary:Both cooling blankets and cold intravenous fluids help lower body temperature in heatstroke, but we are still learning how they differently affect the body.In animal studies, cold fluids given through veins worked better than just using cooling blankets - they protected both heart and kidneys from damage and reduced inflammation, even though both methods cooled the body equally fast.Using cold fluids together with cooling blankets cooled rats faster and more effectively, leading to less organ damage and fewer dangerous inflammation reactions.More research is needed to determine the best combination of cooling methods to help classic heatstroke patients recover better.

Keywords: heatstroke, cooling blanket, cold fluid infusion, cold water immersion, cooling rate, inflammation cytokine