LONDON (Reuters) – As Europe becomes the epicentre of the global coronavirus outbreak, national authorities are becoming increasingly concerned about a potential lack of ventilators, one of the key pieces of equipment needed to treat patients.

Here are some quick facts about them:

– Ventilators are mechanical breathing devices that use pressure to blow air – or a mixture of gases such as oxygen and air – into the lungs. They are crucial to the care of people with lung failure, which can be one of the complications suffered by patient’s with severe cases of COVID-19.

– Ventilators can also be set to exhale the air, effectively taking over both the inhale and exhale functions. They can be set to “breathe” at a certain rate according to a patient’s needs.

– The first respirators date back to the 1920s and 1930s and were known as “iron lungs”. They were often used to help in the treatment of patients with the viral disease polio.

– Today, ventilators are mainly used in intensive care medicine and emergency medicine, but are also used when a patient undergoing surgery is heavily anaesthetised.

– Ventilators are made by numerous companies, including Hamilton Medical of Switzerland, Germany’s Draegerwerk, Getinge Group of Sweden, Ireland-headquartered Medtronic, the Netherlands’ Philips and many other companies.

(Reporting by Kate Kelland and John Miller; editing by Nick Macfie)