Evidence shows that pulmonary problems in coronavirus disease 2019 (COVID-19) may set off from vascular injury that progresses to physiological disturbances through a compromised gas exchange, following an infection with the severe acute respiratory syndrome coronavirus 2 . In this process, inefficient gas exchange in the alveolar could precipitate silent nonclinical hypoxemia . Unfortunately, patients with``silent hypoxemia '' do not necessarily experience any breathing difficulty (dyspnea) at the early stage of COVID-19 while the disease progresses . As a result, several asymptomatic, presymptomatic and patients with mild symptoms may escape quarantine measure and thus continue to spread the virus through contacts . Therefore, early diagnosis of``silent hypoxemia", which attracts no clinical warnings, could be an important diagnostic measure to prevent acute respiratory distress syndrome from the risk of pulmonary failure among the presymptomatic and as a screening tool in the asymptomatic who are hitherto potential spreaders of the virus.
Index: Acute respiratory diseases, COVID-19, Dyspnea, Gas exchange, Oximetry, Pulmonary disorder, SARS-CoV-2, Silent hypoxemia