Catabolism highly influences ICU-acquired hypernatremia in a mainly trauma and surgical cohort.

PURPOSE: To further analyse causes and effects of ICU-acquired hypernatremia. METHODS: This retrospective, single-centre study, analysed 994 patients regarding ICU-acquired hypernatremia. Non-hypernatremic patients (n = 617) were compared to early-hypernatremic (only before ICU-day 4; n = 87), prolonged-hypernatremic (before and after ICU-day 4; n = 169) and late-hypernatremic patients (only after ICU-day 4; n = 121). Trends in glomerular filtration rate (eGFR), urea-to-creatinine ratio (UCR), fraction of urea in total urine osmolality and urine sodium were compared. Risk factors for i) the development of hypernatremia and ii) mortality were determined. RESULTS: Thirty-eight percent (n = 377) developed ICU-acquired hypernatremia. Specifically in the prolonged- and late-group, decreased eGFRs and urine sodium but increased UCR and fractions of urea in urine osmolality were present. Decreased eGFR was a risk factor for the development of hypernatremia in all groups; disease severity and increased catabolism particularly in the prolonged- and late-hypernatremic group. Increased age, SAPS-III and signs of catabolism but not the development of hypernatremia itself was identified as significant risk factor for mortality. CONCLUSIONS: Late- and prolonged-hypernatremia is highly related to an increased protein metabolism. Besides excessive catabolism, initial disease severity and a decrease in renal function must be considered when confronted with ICU-acquired hypernatremia.

Effects of environmental factors on severity and mortality of COVID-19

BackgroundMost respiratory viruses show pronounced seasonality, but for SARS-CoV-2 this still needs to be documented. MethodsWe examined the disease progression of COVID-19 in 6,914 patients admitted to hospitals in Europe and China. In addition, we evaluated progress of disease symptoms in 37,187 individuals reporting symptoms into the COVID Symptom Study application. FindingsMeta-analysis of the mortality risk in eight European hospitals estimated odds ratios per one day increase in the admission date to be 0.981 (0.973-0.988, p<0.001) and per increase in ambient temperature of one degree Celsius to be 0.854 (0.773-0.944, p=0.007). Statistically significant decreases of comparable magnitude in median hospital stay, probability of transfer to Intensive Care Unit and need for mechanical ventilation were also observed in most, but not all hospitals. The analysis of individually reported symptoms of 37,187 individuals in the UK also showed the decrease in symptom duration and disease severity with time. InterpretationSeverity of COVID-19 in Europe decreased significantly between March and May and the seasonality of COVID-19 is the most likely explanation. Mucosal barrier and mucociliary clearance can significantly decrease viral load and disease progression, and their inactivation by low relative humidity of indoor air might significantly contribute to severity of the disease.