Full details of the evidence and the committee's discussion are in evidence review H: surgery (decompressive hemicraniectomy). Terms used in this guideline This section defines terms that have been used in a particular way for this guideline. For other definitions, see the NICE glossary. High-intensity mobilisation High-intensity mobilisation refers to the very early mobilisation intervention from the AVERT trial. (Further details of the intervention performed in the trial can be found in NICE's evidence review F: very early mobilisation.) It includes mobilisation that: begins within the first 24 hours of stroke onset includes at least 3 additional out-of-bed sessions compared with usual care focuses on sitting, standing and walking (that is, out of bed) activity. 2022 Additional information The committee felt that 'immediately' is defined as 'ideally the next slot and definitely within 1 hour, whichever is sooner'. In May 2019, not all devices with a CE mark for thrombectomy were intended by the manufacturer for use as recommended here. The healthcare professional should follow relevant professional guidance, taking full responsibility for the decision. Informed consent should be obtained and documented. Medicines and Healthcare products Regulatory Agency (MHRA) advice remains to use CE-marked devices for their intended purpose where possible. See MHRA's guidance on off-label use of a medical device for further information. There may be a subgroup of people for whom the risk of venous thromboembolism outweighs the risk of haemorrhagic transformation. People considered to be at particularly high risk of venous thromboembolism include anyone with complete paralysis of the leg, a previous history of venous thromboembolism, dehydration or comorbidities (such as malignant disease), or who is a current or recent smoker. Such people should be kept under regular review if they are given prophylactic anticoagulation. 