ABSTRACT
Worldwide concern has been focused on the airborne disease of the COVID-19 pandemic. This study investigated the effect of the limited space air stability on the mechanism of SARS-CoV-2 spreading in the interpersonal breathing microenvironment using an unsteady computational fluid dynamics (CFD) method. A validated numerical model was employed to simulate the transient SARS-CoV-2 releasing process from normal breathing activity. The computational domain was divided into an interpersonal breathing microenvironment and the rest macroenvironment. A displacement ventilation system was implemented with 1.5 ACH, 3 ACH, 7.4 ACH and 9 ACH. Two standing CSPs (Computational Simulated Person) were placed in the middle of the macroenvironment face-to-face with a relative distance of 1 m. Simulation results indicated that in stable cases, the exhaled SARS-CoV-2 tended to accumulate in the interpersonal breathing microenvironment and resulted in a relatively high infection risk for people;whereas in cases where unstable air presented, SARS-CoV-2 concentration was significantly reduced. The unstable conditions lowered the risk of person-to-person transmission in confined spaces. Also, it was found that unstable cases performed better in energy efficiency in comparison with the stable conditions.
ABSTRACT
Severe and critical coronavirus pneumonia 2019 (COVID-19) often occurs in elder patients with multiple comorbidities, and severe hypoxemia events constitute a key factor for the deterioration of some cases. The critical type of COVID-19 could progress into acute respiratory distress syndrome and multi-organ dysfunction, which are the major causes of death. Early non-invasive ventilation (NIV) treatment of possible pathophysiological abnormalities is helpful to improve prognosis. Close monitoring of oxygenation, reducing patients' oxygen consumption, active psychological intervention, and rapid handling of severe hypoxemia events are the key factors for successful NIV treatment. In addition, active adjuvant therapies such as correcting coagulation dysfunction, providing proper nutritional support, accurate volume control, and safe individualized blood glucose monitoring are of great significance.