[Research progress of heatstroke warning system].

With global warming and frequent heat waves, the incidence of heat-related-illness has gradually increased, and heatstroke is the most serious clinical syndrome, with high mortality and incidence of sequelae. Effective heatstroke warning aims to reduce the incidence and the harm of heatstroke by monitoring certain parameters and forecasting the possibility of suffering heat illness, however, there is no unified summary of the heatstroke early warning system at present. The occurrence of heatstroke involves two key aspects: climate environment and individual susceptibility, and individual susceptibility is manifested as the difference in heat tolerance ability. This article represents the current early warning system of heatstroke from climate environment, such as effective temperature, heat index, wet bulb globe temperature (WBGT) index, somatosensory temperature, etc., and individual susceptibility, for the reference of research and development in this field.

Immune Cells Characteristics and Their Prognostic Effects in Exertional Heatstroke Patients: A Retrospective Cohort Study.

Background: Exertional heatstroke (EHS) remains a major problem for those who take strenuous physical activity. Inflammation and immune dysfunction were thought to be crucial to the pathophysiological process of heatstroke. The present study was aimed to investigate the dynamic changes of the immune cells in patients with EHS and determine their prognostic effects to provide the clinical evidence of the above process. Methods: This single-center retrospective cohort study collected all patients with EHS admitted to the intensive care unit (ICU) of the General Hospital of Southern Theater Command of PLA from October 2008 to May 2019. The dynamic changes of the main immune cell count and ratio were collected, including white blood cell (WBC), neutrophil, monocyte, and lymphocyte. The neutrophil-to-lymphocyte ratios (NLR) were calculated by the neutrophil count/lymphocyte count × 100%. The main outcome was 90-day mortality. Results: A total of 189 patients were enrolled. For survivors, after 24 h, the WBC and neutrophil counts began to decrease, and they were back to normal in 72 h. In addition, the lymphocyte counts were within normal limits all the time. For non-survivors, the WBC and neutrophil counts were continuous over the normal range, while the lymphocyte count and the ratio began to decrease after 24 h and were continuously low in the following days. Receiver operating characteristic (ROC) curves analysis showed that increased neutrophils and decreased lymphocytes were associated with the poor prognosis of the patients. A prediction model based on immune cell counts and ratios was constructed, and the lymphocyte count was accounted for the maximum weight. Conclusions: In patients with EHS, increased neutrophils and decreased lymphocytes were associated with the poor prognosis. The lymphocyte count at 72 h after admission was the most important prognostic factor.

Characteristics and Outcome of Exertional Heatstroke Patients Complicated by Acute Hepatic Injury: A Cohort Study.

BACKGROUND AND AIMS: Exertional heatstroke (EHS) is associated with strenuous physical activity in hot environments. The present study aimed to investigate dynamic changes of hepatic function indices in EHS patients and determine risk factors for death. METHODS: This single-center retrospective cohort study considered all patients with EHS admitted to the intensive care unit at the General Hospital of Southern Theater Command of PLA from October 2008 to May 2019. Data on general characteristics, organ function parameters, and the 90-day outcome of enrolled patients were collected. Hepatic indices were collected dynamically, and patients with acute hepatic injury (AHI) were identified by plasma total bilirubin (TBIL) ≥34.2 µmol/L and an international normalized ratio ≥1.5, or with any grade of hepatic encephalopathy. RESULTS: In patients who survived, TBIL, alanine aminotransferase and aspartate aminotransferase were increased at 24 h, peaked at 2-3 days, and began to decrease at 5 days. In non-survivors, TBIL continuously increased post-admission. The area under the receiver operating characteristic curve for the prediction of mortality based on sequential organ failure assessment (SOFA) scores was 89.8%, and the optimal cutoff value was 7.5. Myocardial injury and infection were identified as independent risk factors for death in EHS patients with AHI. CONCLUSIONS: In EHS patients, hepatic dysfunction usually occurred within 24 h. Patients with AHI had more severe clinical conditions, and significantly increased 90-day mortality rates. SOFA scores over 7.5, complicated with myocardial injury or infection, were found to be risk factors for death in EHS patients with AHI.