Among the 8 patients included in the study, 3 died (37.5%) and 5 survived during their ED care in the first 24 h of admission. (Table 1). Individual patient characteristics are presented in Supplementary Table 1. Patients who died were younger, with a median age of 47 years, compared to 69 years for those who survived (p = 0.393). Patients who died were all males. Several patients developed hyperthermia after prolonged exposure to elevated environmental temperatures during outdoor activities or labor. Others experienced heat stroke in their homes or public spaces. Common metabolic, cardiovascular and psychiatric predisposing comorbidities increased patient’s susceptibility to heat stroke.

Patients who died had significantly lower pH (7.067 vs. 7.4; p = 0.036, Cliff’s delta = 1.0, 95% CI [-0.395, -0.015]) and higher potassium (7.3 vs. 3.2 mmol/L; p = 0.036, Cliff’s delta = -1.0, 95% CI [3.23, 4.77]) and calcium levels (1.19 vs. 0.97 mmol/L; p = 0.036, Cliff’s delta = -1.0, 95% CI [0.06, 0.38]) on initial blood gas analysis. Lactate was elevated in both groups but significantly higher in those who died (10.9 vs. 3.5 mmol/L; p = 0.036, Cliff’s delta = -1.0, 95% CI [4.80, 20.13]). Median base excess was lower in non-survivors (-13.8 vs. -6.0 mmol/L; p = 0.071, Cliff’s delta = 0.87, 95% CI [-15.4, -2.0]), though this difference did not reach statistical significance. Creatine kinase, D-dimer, and liver enzymes showed differences but were not statistically significant due to limited data (Supplementary Table 1).

Head CT scans were performed on six out of eight patients. One patient who died shortly after admission, exhibited signs of diffuse brain edema and herniation on the CT scan. No abnormalities were detected in the scans of the surviving patients (Fig. 4).

Representative CT images (axial and coronal slices; ST: 5 mm) demonstrating diffuse cerebral edema; loss of gray-white matter differentiation, compression of internal and external liquor spaces with effacement of basal cisterns

All patients in both groups were given cooled intravenous infusions using a balanced crystalloid solution. There was no significant difference in the volume of cooled intravenous infusions between survivors and non-survivors (2000 ml vs. 1500 ml; p = 0.544, Cliff’s delta = 1.0 95% CI [189, 3411]). The body cavity lavage procedure was not performed on any of the survivors except one, while it was carried out on all but one of the patients who died (Table 2).