"Silent or Happy Hypoxemia" in COVID-19: Does it exist?

Abstract

Since the end of 2019, SARS-CoV2 coronavirus infection has expanded quickly from Asia to become pandemic. Health system was stressed all around the world and most of the health care was redirected to manage patients with COVID-19. But there was a subgroup of patients that drew the attention of physicians because an important hypoxemia is associated with neither symptom of ventilatory insufficiency nor dyspnea. Some authors called this phenomenon “happy” or “silent hypoxemia”. Our objective is to review main aspects of its physiopathology.