In a normal person, oxygen saturation will be 98%-100% in normal times. In this group of patients with novel coronavirus infection, the oxygen saturation may not be significantly affected for the normal and mild type of patients. However, for patients with the heavy and critical type, they will have respiratory distress and may experience a decrease in oxygen saturation, and in severe cases, even respiratory failure, where oxygen saturation will be less than 90% and the partial pressure of oxygen in respiratory failure will be less than 60% when blood gas analysis is checked. For hypoxemia that is difficult to correct, tracheal intubation connected to an invasive ventilator is required to assist breathing to prevent systemic functional impairment from low oxygen concentration. If the patient is an elderly patient, or someone who has had chronic airway disease in the past, such as chronic obstructive pulmonary disease or pulmonary fibrosis, the usual oxygen saturation in this group of patients will be low, possibly below 90%, or even lower in the long-term tolerated state, and such a patient will experience a rapid drop in oxygen saturation, lower than usual, in severe cases after infection with the novel coronavirus.