Covid-19: Brazil hospitals 'run out of oxygen' for virus patients

The problem are the oxygen cylinders. (I'd like that journalist had a technical check in addition to the spell check.) The cylinders are used to give a mix of pure oxygen and air to the patients in ventilators.

(Also in some places, they use the oxygen cylinders to give a mix of air and oxygen to patient that don't need a ventilator, but are in a bad condition. A ventilator is a quite invasive treatment, and is better to avoid it when possible.)

From https://en.wikipedia.org/wiki/Ventilator#Function

> In its simplest form, a modern positive pressure ventilator consists of a compressible air reservoir or turbine, air and oxygen supplies, a set of valves and tubes, and a disposable or reusable "patient circuit". The air reservoir is pneumatically compressed several times a minute to deliver room-air, or in most cases, an air/oxygen mixture to the patient.