[Protective effect of mild hypothermia at different starting times on organ function in patient with exertional heat...

To investigate the protective effect of mild hypothermia at different starting times on the physiological functions of the viscera of exertional heat stroke (EHS).

A prospective randomized controlled trial was conducted. EHS patients admitted to intensive care unit of the 159th Hospital of People's Liberation Army and the First Affiliated Hospital of Zhengzhou University from June 2015 to June 2017 were enrolled. The patients were divided into 2, 4, 6 hours start hypothermia treatment groups according to the random number table method, the mild hypothermia was initiated at 2, 4 and 6 hours after the disease onset respectively, and the methods were the same in each group. After treatment of 2, 12, 24 hours, the venous blood in the three groups was collected to detect serum cardiac troponin I (cTnI) with chemiluminescence method, MB isoenzyme of creatine kinase (CK-MB) with immunosuppressive method, creatinine (Cr) with creatine oxidase method, β₂-microglobulin (β₂-MG) with turbidimetry, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) with enzyme method. Multiple organ dysfunction syndrome (MODS) within 24 hours after treatment was recorded. Linear regression analysis of the correlation between mild hypothermia start-up time and MODS was done.

Ninety-three cases of EHS were included, with 32, 31 and 30 patients in 2, 4, 6 hours start treatment groups respectively. There were no significant differences in gender, age, core temperature, onset time to admission, Glasgow coma scale (GCS), acute physiology and chronic health evaluation system II (APACHE II) score at admission among the three groups. There were no significant differences in the levels of serum cTnI, CK-MB, Cr, β₂-MG, ALT and AST at 2 hours after treatment. But with the prolongation of the treatment time, all indicators gradually increased. And the earlier start of the mild hypothermia, the less significant of the above indexes. All indexes in 2 hours start treatment group were significantly lower than those of 2 hours and 6 hours start treatment groups at 24 hours after treatment [cTnI (ng/L): 49.53±9.25 vs. 56.52±10.05, 64.57±11.21; CK-MB (U/L): 51.47±11.83 vs. 57.87±7.43, 64.40±7.93; Cr (μmol/L): 140.97±11.33 vs. 148.16±10.39,155.57±8.65; β₂-MG (mg/L): 10.28±1.46 vs. 11.58±2.13, 12.93±1.98; ALT (U/L): 248.53±75.47 vs. 341.42±129.58, 425.77±101.23; AST (U/L): 197.25±42.59 vs. 292.81±58.49, 351.20±60.41, all P < 0.05]. There was significant difference in the incidence of MODS in 2, 4, 6 hours start treatment groups [43.75% (14/32), 64.52% (20/31), 80.08% (24/30), χ² = 8.761, P = 0.013]. Linear regression analysis showed that the earlier onset time of mild hypothermia, the lower incidence of MODS (R² = 0.915, P = 0.013).

The application of mild hypothermia in 2 hours can effectively protect the physiological function of EHS organs and reduce the incidence of MODS.