Diagnosing and treating intracerebral haemorrhage in the ambulance

4 days ago
4 min read

Bright yellow-green emergency ambulance speeds past brick houses on a suburban street, with blurred motion and visible NHS text.

Why diagnose intracerebral haemorrhage in the ambulance?

Intracerebral haemorrhage (ICH) is caused by sudden, spontaneous bleeding into the brain. We know that once bleeding starts, it causes irreversible damage to the brain. Bleeding often continues in the first few hours, worsening the damage that has already occurred. If this continues unchecked, it may be life threatening. Currently, paramedics and stroke clinicians can’t tell who has had an intracerebral haemorrhage and who has had other types of strokes until they do a brain scan in hospital. In the UK, the average time from symptoms starting to arriving at hospital is over four hours, so ICH patients often miss the chance to prevent this further bleeding. The prehospital phase of stroke care represents a vital opportunity to catch ICH as early as possible and start time-critical treatments.

How might we diagnose intracerebral haemorrhage?

Specialised stroke ambulances equipped with CT scanners, called mobile stroke units, have been tested in a few locations around the world. These can be used to diagnose ICH in the ambulance, but they are very expensive to buy and operate, which currently prevents their widespread use. For as many ICH patients as possible to be able to start treatment in the ambulance, paramedics need a simpler, cheaper, and accurate diagnostic tool. A marker in the blood called glial fibrillary acidic protein (GFAP) has shown promise in detecting ICH. GFAP’s accuracy can be improved by combining it with clinical features that are more common in patients with ICH, such as very high blood pressure and reduced consciousness. GFAP can be detected in minutes using a fingerprick blood sample and a simple lateral flow test and when combined with clinical features, GFAP could provide the simple diagnostic tool we need. The Greater Manchester DIAGNOSIS study is testing the accuracy of this combined diagnostic model and will complete in early 2027.

What treatments could be given?

The optimal time to start treatment for ICH is at the onset of symptoms, when the risk of haematoma expansion is highest. Haematoma expansion, where a collection of blood continues to increase in size, is an indicator of poor prognosis and provides a key target for early treatment in ICH care. Around 20% of ICH patients will be taking blood thinners (anticoagulation) and giving treatments to reverse these blood thinners can prevent further bleeding. High blood pressure is also linked to more bleeding and intensive lowering of blood pressure with intravenous drugs has been shown to improve recovery. Whilst these treatments are effective in hospital, earlier intervention in ambulances is likely to be more effective. This has recently been proven in a trial called INTERACT4, which tested intensive lowering of blood pressure in ambulances for all suspected stroke patients. The trial included both types of strokes and found it effective for ICH but harmful for strokes caused by blockage of an artery (ischemic strokes).

Overall, 45% more ICH patients who had blood pressure lowering were living independently at 90 days. For ischaemic stroke patients treated with blood pressure lowering, 8% less were living independently at 90 days. This further highlights the importance of developing an accurate diagnostic tool for the ambulance; treatments that help ICH patients may cause some harm for other patients.

How good will the test have to be?

Research suggests that if a test was used to diagnose ICH in the ambulance, positive tests would need to be correct at least 39% of the time for patients to benefit overall. If positive tests were right two-thirds of the time this would lead to major benefit; for every 1000 patients with positive tests treated with blood pressure lowering in the ambulance, 130 would be less disabled long-term, including 50 more achieving functional independence.

What are we planning to do next?

Taking this learning, Abbie’s PhD will support the further development of a diagnostic tool for ICH. The DIAGNOSIS study is well underway and will include 257 participants by early 2027. All participants will have been brought by ambulance to two hospitals in Greater Manchester with a suspected stroke, within six hours of their symptoms starting. Abbie will use the data collected during the DIAGNOSIS study to test the model’s accuracy, determining if it is good enough to give treatments to suspected ICH patients. Refining which clinical features to include in the model will follow, using a real-world dataset of suspected stroke patients from across the Northwest of England. This will ensure that we are developing a test well suited to suspected stroke patients in our region and the wider UK.

It is also vital that the test is simple and practical for paramedics and that we understand their views, and those of patients and hospital stroke clinicians. To do this, Abbie will interview these key stakeholders to explore the feasibility and barriers around implementing our new diagnostic model. This will include assessing practicalities of digital support and solutions, streamlining workflows, understanding perception of risk and willingness to base treatment decisions on the results.

By the end of Abbie’s PhD, the team hope to have a diagnostic test that can be taken forward to clinical trials in ambulances, testing whether we can improve outcomes for ICH patients by delivering blood pressure lowering in the ambulance. This may then lead on to testing other treatments such as reversing blood thinners and giving other drugs to stop bleeding, stopping as much early bleeding as possible and improving outcomes for this sometimes devastating form of stroke

Personal Bio

Smiling woman in a white shirt sits in a small boat on a green river, with leafy trees and other boats behind her.

Abbie has a background in both Medical Sciences and Public Health through completing an undergraduate degree in Medical Sciences at the University of Leeds and is currently undertaking a master’s in Public Health at the University of Manchester.

Throughout her undergraduate degree she developed an interest in neuroscience, completing her dissertation in comparing the accuracy of models in predicting sensory gene expression. Her passion for addressing barriers in healthcare was first developed during her undergraduate placement year in the NHS working to improve access to care and continued throughout her masters.

This amalgamation of experience has led to a clear goal of aiming to improve the provision of quality healthcare and improving health outcomes through early intervention.