Why should COVID-19 patients be treated in a negative pressure room?

The cirulation of air in the rooms of Intensive Care Units (ICU) can be adjusted to either positive of negative pressure. Negative pressure means that the air in the room is not ventilated to the outside or neighbouring rooms, but rather through a central ventilation (tubing to the outside). In contrast positve pressure rooms ventilate the air within the room to the surronding. Negative pressure is used too confine pathogens to a single closed environment and avoid the spread of infectious particles from an infected patient to others (as in COVID-19), while a positive pressure room protects the patient in the room from being infected from infection.