Experts call this phenomenon `silent hypoxia`, which occurs when the patient is not aware that their body is lacking oxygen.
Typically, these patients show Covid-19 symptoms two to seven days before arriving at the hospital.
He spent nearly two weeks volunteering to work in the emergency room at the epicenter of the epidemic.
`The X-rays look terrible. But they are completely awake, can use cell phones. All have been sick for many days. But only recently have they felt short of breath, tired and experiencing
Doctors at Maimonides Medical Center, USA, perform intubation on Covid-19 patients.
This is a dangerous phenomenon because when people infected with nCoV notice signs of respiratory abnormalities, the disease is already in a very severe stage.
`Some even have to use ventilators. Carbon dioxide levels increase, fluid accumulates in the air sacs, their lungs harden, leading to acute respiratory failure,` he added.
Doctors speculate that for some people, Covid-19 symptoms do not progress quickly.
By the time they were hospitalized, severe damage had occurred, not only to the lungs but also to many other organs such as the heart, kidneys and brain.
In the early stages of the pandemic, almost all patients used ventilators after being hospitalized.
To connect to a ventilator, the doctor must intubate.
To avoid the phenomenon of `silent hypoxia`, doctor Richard Levitan calls for early diagnosis by having Covid-19 patients with mild symptoms use a blood oxygen level monitor during two weeks of isolation.
However, the problem is the accuracy of personal meters sold on the market.