Lung Injury in COVID-19 Has Pulmonary Edema as an Important Component and Treatment with Furosemide and Negative Fluid Balance (NEGBAL) Decreases Mortality

The SARS-CoV2 promotes dysregulation of Renin–Angiotensin–Aldosterone. The result is excessive retention of water, producing a state of noxious hypervolemia. Consequently, in COVID-19 injury lung is pulmonary edema. Our report is a case–control study, retrospective. We included 116 patients with moderate–severe COVID-19 lung injury. A total of 58 patients received standard care (Control group). A total of 58 patients received a standard treatment with a more negative fluid balance (NEGBAL group), consisting of hydric restriction and diuretics. Analyzing the mortality of the population studied, it was observed that the NEGBAL group had lower mortality than the Control group, p = 0.001. Compared with Controls, the NEGBAL group had significantly fewer days of hospital stay (p < 0.001), fewer days of ICU stay (p < 0.001), and fewer days of IMV (p < 0.001). The regressive analysis between PaO(2)/FiO(2)BAL and NEGBAL demonstrated correlation (p = 0.04). Compared with Controls, the NEGBAL group showed significant progressive improvement in PaO(2)/FiO(2) (p < 0.001), CT score (p < 0.001). The multivariate model, the vaccination variables, and linear trends resulted in p = 0.671 and quadratic trends p = 0.723, whilst the accumulated fluid balance is p < 0.001. Although the study has limitations, the promising results encourage more research on this different therapeutic approach, since in our research it decreases mortality.