Published date
Friday, 3 February, 2017

Friday 3 February 2017

Funded by the European Union (EU),  a new international study called PROOF will investigate whether high-dose oxygen therapy can reduce the effects of stroke.

What is an ischaemic stroke?

An ischaemic stroke is the most common type of stroke. The arteries that supply the brain with blood become clogged by clots. This kills the brain cells at the centre of the stroke and puts those brain cells nearby at great risk of damage.

The longer the brain suffers from oxygen and blood deficiency, the more serious the consequences, and the more brain tissue will die. Emergency treatment must therefore get rid of the blocked arteries as quickly as possible.

What will happen in the PROOF trial?

Starting in February 2017 at the Tübingen University Clinic - and at eleven other clinical centres in eight European countries – the PROOF trial will test whether the consequences of stroke can be reduced by rapidly applying high-dose oxygen therapy to new patients.

The high-dose oxygen therapy is very simple and low-cost. After having been diagnosed with an ischaemic stroke after their scan, the patient wears a mask through which they inhale almost pure oxygen at a flow of 40 litres per minute. This keeps the oxygen content in the blood as high as it can be.

The aim is to ensure that the surrounding brain tissue at risk, which will have less oxygen but is not yet dead, is stabilized by the high oxygen content coming in. This continues until the clot is removed and the blood circulation is improved again. The treatment therefore aims at the so-called "shadow zones" of the stroke, sometimes called the "rescue zones". These may include the entire stroke area in some patients.

What could the PROOF trial mean for stroke patients?

PROOF is the first trial to thoroughly investigate high-dose oxygenation in stroke patients. If it proves that the brain can be saved by this treatment, it could also bring great benefits to patients who are not near a clinic where stroke can be treated, and who have longer access times to emergency care.

Coordination of the PROOF trial, funding and member group

The study is coordinated by Dr Sven Poli, Senior Physician of the Department of Neurology with focus on neurovascular diseases at the University Hospital Tübingen. The Europe-wide study is funded by the European Union with a grant of about six million euros. 

The Stroke Association is a member of the Stroke Alliance For Europe (SAFE), which will work on communication of information about the PROOF trial to non-clinical audiences. For further detail please contact

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