Thankfully, most COVID-19 patients do not experience severe symptoms. In those cases in which a patient does need to be hospitalised, there are currently no treatments available to target the virus itself. Consequently, the primary aim of hospitalisation is to keep the patient alive while the infection is resolved.
As COVID-19 is a respiratory infection first and foremost, hospital treatment’s primary goal is to maintain oxygen levels in the lungs and thereby the blood. If simple administration of oxygen is not sufficient to achieve this, then movement of gases in and out of the lungs can be aided using oxygen under pressure (CPAP) or mechanical ventilation. In a very small number of cases in which the lungs are severely damaged, patients blood can be oxygenated outside the body by a machine, allowing the lungs to rest.
In severe cases, the function of other organs can also be impaired. The kidneys perform the essential role of filtering the blood, removing waste products and controlling salt and fluid volume. Should kidney function be severely impaired, blood filtration can be performed by a machine outside the body (dialysis). Patients can also develop life-threateningly low blood pressure, which can cause widespread organ damage due to lack of oxygen. Blood pressure can be maintained with drugs (such as noradrenaline).
How is coronavirus disease treated in hospital?: https://coronavirusexplained.ukri.org/en/article/vdt0008/