Pre Hospital Brain Imaging

Dr. Mark Wilson, Imperial Hospitals NHS Trust and London Air Ambulance

The Hyper-acute Management of Brain Injury – on scene imaging

Trauma is the most common cause of death in the under 45s and traumatic brain injury (TBI) is the most common underlying mechanism. TBI also has considerable morbidity resulting in long-term disability, which has considerable costs to the patient’s family and society as a whole. Over the last two decades, research has focused on the “In hospital” phase of care in particular optimising treatment on Intensive Care. However, by this time, much of the secondary injury (the inPre Hospital Brain Imaging_Mark Wilsonjury that evolves after the moment of impact) has irreversibly damaged brain tissue that will not recover. The best ITU care can offer is slowing progression of injury – it can’t bring back dead brain tissue. This study aims to take diagnosis closer to the point of injury. In the “Pre-Hospital” arena, TBI is classified as one condition and protocols are written to treat the generic “brain injury”. There are however many forms of brain injury (e.g. extradural, subdural, subarachnoi
d blood, diffuse axonal, hypoxia…) that individually almost certainly have optimal specific treatments. The problem has been that pre-hospital imaging has not been possible and hence pre-hospital specific diagnosis and treatments has not occurred. This study assesses the accuracy of using a near infrared assessment tool to establish if a patient has a blood clot on the outside of the brain (an extradural or subdural haematoma). Two protocols will run concurrently, one investigating the use of near infra-red in the pre-hospital environment (with London’s Air Ambulance) and another, on a separate group of patients, studying its use in the resuscitation department of St Mary’s Hospital Major Trauma Centre. The results of the near Infrared assessment will then be compared with the results of CT scan and need for surgical intervention with the sensitivity and specificity for the technique calculated. By developing a technique of earlier diagnosis, specific brain injuries can be managed in a more targeted manner. For example, blood pressure (important for maintain brain blood flow) could be optimised and theatres prepared if there is earlier awareness that a patient with a blood clot needs urgent surgery. In the remote environment such techniques could enable earlier surgical intervention. We are in an era when neurotrauma research must change to focus on the pre-hospital period. This is the time when brain tissue loss can be prevented. Whilst this study has important implications for bio-enginering, the main beneficiary will be patients, their relatives and society from minimising secondary brain injury.