Targeted temperature management in patients with severe heatstroke: Three case reports and treatment recommendations

Abstract

Rationale: Unprecedented heatwaves over the past several years are getting worse with longer duration in the course of global warming. Heatstroke is a medical emergency with multiple organ involvement and life-threatening illness with a high mortality rate of up to 71%. Uncontrolled damage to the central nervous system can result in severe cerebral edema, permanent neurological sequelae, and death. However, regarding the therapeutic aspects of heat stroke, there was no therapeutic strategy after the rapid cooling of the core body temperature to <39°C to prevent further injury.

Patient concerns: Each of 3 patients developed a change of mental statuses after the exposure to summer heatwaves or relatively high environmental temperatures with high humidity in the sauna.

Diagnoses: The patients were diagnosed with severe heatstroke since they showed cerebral edema and multiple organ dysfunction based on the results from laboratory tests and the findings in brain computed tomography scan.

Interventions: The patients underwent induced therapeutic hypothermia (<36°C) between 24 and 36 hours in the management of severe heatstroke.

Outcomes: The patients survived from cerebral edema and multiple organ dysfunction.

Lessons: We believe that targeted temperature management (<36°C) will help treat severe heatstroke. Thus it should be considered for reducing the chance of development of complications in multiple organs, especially in the central nervous system, when managing patients with severe heatstroke.

Figure 1

Changes in laboratory results after hospital admission. (A) Aspartate aminotransferase, (B) Troponin-I, (C) Lactic acid, (D) Prothrombin time. Laboratory test results, representative of systemic organs, increased rapidly out of normal range after admission to the ICU, even though the initial heat insult was removed from patients. Then, all values of laboratory results rose to the highest between hospital days 2 and 4. Targeted temperature management might weaken further injuries subject to initial heat insult in multiple organs.

Figure 2

Pathophysiology of heatstroke and target of therapeutic-induced hypothermia. Targeted temperature management could prevent multiple-organ failure, including CNS injury, from aggravating in patients with heatstroke because it could reduce the overwhelming immunologic responses and direct thermal injury to the CNS in the dotted box.