Comparison of cooling methods for drug-induced hyperthermia in a pre-hospital and emergency department setting: a systematic review.

INTRODUCTION: Hyperthermia is a medical condition characterized by elevated body temperature above 39.0 °C due to imbalanced heat production and dissipation. Stimulant drugs such as cocaine and amfetamines, as well as intense physical exertion, commonly induce hyperthermia. In severe cases, hyperthermia presents life-threatening complications requiring immediate temperature reduction interventions. Management involves various cooling modalities that differ in efficacy and practicality within pre-hospital and emergency department settings. This systematic review evaluates and compares the efficacy of cooling modalities for managing drug-induced hyperthermia suitable for pre-hospital and emergency department settings. Due to the paucity of data on drug-induced hyperthermia, studies examining exercise-induced hyperthermia were also included to provide additional evidence on cooling efficacy.

METHODS: A comprehensive search for cooling efficiency studies across PubMed, Embase, Cochrane Central Register of Controlled Trials, CINAHL, APA PsycINFO, and SportDiscus from inception until October 2025, without language restrictions was conducted. Randomized controlled trials, observational studies, and case-based studies were included. Quality assessment utilized the GRADE approach for certainty of evidence, while the Newcastle-Ottawa Scale and RoB 2.0 assessed risk of bias. Meta-analysis was performed when feasible.

RESULTS: The search identified 6,920 citations, with 71 studies included in this systematic review comprising 1,932 patients treated with 12 different cooling modalities. Analysis demonstrated that an ice water immersion cooling rate of (0.169 ± 0.027 °C/min) and cold water immersion cooling rate of (0.162 ± 0.037 °C/min) achieved the highest cooling rates. Meta-analyses confirmed that cold water and ice water immersion were more effective than passive cooling. Ice water-soaked sheets or towels had a cooling rate of (0.121 ± 0.030 °C/min) and room temperature immersion a cooling rate of (0.089 ± 0.020 °C/min) produced adequate cooling rates, while all other cooling modalities proved inadequate as standalone treatments.

DISCUSSION: Due to paucity of data on cooling methods specifically for drug-induced hyperthermia, this study incorporates data from exertional hyperthermia to inform treatment recommendations. Both populations share similar demographics and involve exertion as a primary or contributing factor, supporting the clinical relevance of this approach. However, important pathophysiological differences exist; in case of exertional heat stroke hyperthermia related to exertion improves as physical activity ceases, while stimulant-induced hyperthermia persists despite cessation of activity due to ongoing central drug effects. Although sedation can reduce physical activity in intoxicated patients, these patients often present with concurrent medical complications requiring simultaneous monitoring and treatment.

CONCLUSION: When ice or cold water immersion is available, often at large events, and can be applied safely, this represents the preferred cooling method. For emergency and pre-hospital settings, ice water-soaked sheets or towels are a practical cooling method available to most emergency departments and pre-hospital settings to treat hyperthermic intoxicated patients that is less resource intensive than immersion techniques and maintains continuous patient monitoring capabilities. Given the limited data on drug-induced hyperthermia, further research should address these knowledge gaps and investigate combined cooling strategies and their practicality in pre-hospital and emergency department settings.