PHYSIOLOGICAL EFFECTS AFTER EXPOSURE TO HEAT: A BRIEF LITERATURE REVIEW

Many employees are exposed to heat stress during their work. Although the direct effects of heat are well reported, the long term physiological changes after heat exposure are hardly described. The present manuscript addresses these issues in the form of a brief literature review. Repeated heat exposure results in heat acclimatization, these physiological adaptations decay gradually afterwards, re-increasing the vulnerability to heat injuries. Repeated heat exposure may lead to kidney damage (related to dehydration) and reduced efficiency of the reproductive system. A history of heat stroke may increase the sensitivity to heat illness. The increased susceptibility possibly indicates an impaired thermoregulatory system resulting from a heat stroke, or a genetic predisposition prior to the first heat stroke

Prognostication using SpO(2)/FiO(2) in invasively ventilated ICU patients with ARDS due to COVID-19-Insights from the PRoVENT-COVID study

Background: The SpO(2)/FiO(2) is a useful oxygenation parameter with prognostic capacity in patients with ARDS. We investigated the prognostic capacity of SpO(2)/FiO(2) for mortality in patients with ARDS due to COVID-19.Methods: This was a post-hoc analysis of a national multicenter cohort study in invasively ventilated patients with ARDS due to COVID-19. The primary endpoint was 28-day mortality.Results: In 869 invasively ventilated patients, 28-day mortality was 30.1%. The SpO(2)/FiO(2) on day 1 had no prognostic value. The SpO(2)/FiO(2) on day 2 and day 3 had prognostic capacity for death, with the best cut-offs being 179 and 199, respectively. Both SpO(2)/FiO(2) on day 2 (OR, 0.66 [95%-CI 0.46-0.96]) and on day 3 (OR, 0.70 [95%-CI 0.51-0.96]) were associated with 28-day mortality in a model corrected for age, pH, lactate levels and kidney dysfunction (AUROC 0.78 [0.76-0.79]). The measured PaO2/FiO(2) and the PaO2/FiO(2) calculated from SpO(2)/FiO(2) were strongly correlated (Spearman's r = 0.79).Conclusions: In this cohort of patients with ARDS due to COVID-19, the SpO(2)/FiO(2) on day 2 and day 3 are independently associated with and have prognostic capacity for 28-day mortality. The SpO(2)/FiO(2) is a useful metric for risk stratification in invasively ventilated COVID-19 patients. (C) 2021 The Authors. Published by Elsevier Inc