Clinical guidelines are developed by multi-disciplinary teams of experts in their fields, who review all of the evidence for specific interventions to assess what should be done in health care settings. In the case of stroke there are many guidelines dealing with specific parts of the care pathway – for example on the emergency treatment of ischaemic stroke, or swallowing problems.
The European Stroke Organisation (ESO) publishes a variety of guidelines covering specific interventions along the whole stroke care pathway. https://eso-stroke.org/guidelines/eso-guideline-directory/#acute-stroke-closed.
There are also over-arching guidelines that assess the evidence across the whole care pathway and provide recommendations for best practise. Where evidence is sparse these recommendations may be agreed by a consensus of the guideline development group. For example, in the UK the Royal College of Physicians publish The UK’s National Clinical Guideline for Stroke https://www.strokeaudit.org/Guideline/Full-Guideline.aspx.