SHED - Subarachnoid Haemorrhage in the Emergency Department
Research type
Research Study
Full title
External validation of a clinical decision rule and neuroimaging rule out strategy for exclusion of subarachnoid haemorrhage in the emergency department: A prospective observational cohort study
IRAS ID
253791
Contact name
Beverley Greenhalgh
Contact email
Sponsor organisation
Northern Care Alliance
Duration of Study in the UK
0 years, 6 months, 28 days
Research summary
Research Summary
Our aim is to understand how best to investigate acute severe headaches, which are suggestive of a condition called subarachnoid haemorrhage (SAH). SAH is a potentially severe cause of headache in the UK and requires urgent identification and treatment. It is defined as the presence of blood within one of the layers of the brain. At its most serious, it can cause death and severe disability. \n\nWe want to understand the accuracy of CT brain scanning in the Emergency Department (ED) and how this accuracy changes with time.\n\nWe will collect data on patients presenting to the Emergency department that have headaches reaching peak intensity within one hour. These are the classic headache patterns that raise concern with clinicians about the possibility of SAH. We will use this data to try and validate recently proposed clinical rules, and CT brain strategies, which suggest they can exclude the possibility of SAH with a high degree of precision.\n\nWith this information, we will be able to inform clinicians how accurate CT brain scans are safely excluding SAH. Further to this, we will highlight how this accuracy changes depending on the timing of the scan, using hourly intervals from onset of the headache. We will also evaluate the accuracy of clinical decision rules (without any brain scans) to exclude the condition of SAH.Summary of Results
Background and study aim:
The SHED study aimed to understand how acute headaches are dealt with by the Emergency Department (ED). We wanted to understand what tests are used by clinical teams to exclude the most serious cause of acute headache, a bleed on the brain (known as a subarachnoid haemorrhage). We also wanted to study the accuracy of these tests over time.What did the study involve?
This study didn’t involve any additional treatments or tests, and no extra questions other than those asked routinely by medical professionals.Methods:
Full explanation of the study methodology is contained within our open access protocol, accessible at External validation of a clinical decision rule and neuroimaging rule-out strategy for exclusion of subarachnoid haemorrhage in the emergency department: A prospective observational cohort study | medRxiv https://gbr01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fclick.pstmrk.it%2F3ts%2Fwww.medrxiv.org%252Fcontent%252F10.1101%252F2021.05.26.21257212v1%2FNBTI%2FXlS1AQ%2FAQ%2Fe57b6ecc-d43b-4bb4-b17d-2cf1c2af15b7%2F1%2FWzLMA2i8c-&data=05%7C02%7Cfrenchay.rec%40hra.nhs.uk%7Cfd2e104eb7334555648e08dc74b91532%7C8e1f0acad87d4f20939e36243d574267%7C0%7C0%7C638513585474669557%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=eS%2Bf%2BQqE4ivog5AysuuDoe5qMBzTT5dyvUySn22Es2o%3D&reserved=0Key findings:
Between March 2020 and February 2023, we included 3663 people in this study. 3268 patients (89.2%) underwent CT-brain imaging. There were 237 cases of confirmed subarachnoid haemorrhage, (6.5%).
CT brain imaging within six hours of headache onset (n=772) was very good at excluding the diagnosis of subarachnoid haemorrhage – of all the patients who had a negative test, 99.6% (95% CI 98.9% to 99.9%) did not go on to be diagnosed with subarachnoid haemorrhage. The accuracy of CT imaging remained high over time but did fall to a degree.Conclusions:
Our data suggests a very low likelihood of SAH following a negative CT-brain scan performed early after headache onset. These results can inform shared decision making on the risks and benefits of further investigation to exclude serious cases of acute headache.Dissemination:
We have prepared a manuscript which is currently in peer review at the Emergency Medicine Journal. We have presented the results at several major international conferences, including the Royal College of Emergency Medicine annual scientific conference.
With publication of our findings, we will update the study website to make all information readily accessible to patients and clinicians involved in the project, and the wider clinical community.REC name
South West - Frenchay Research Ethics Committee
REC reference
19/SW/0243
Date of REC Opinion
9 Jan 2020
REC opinion
Favourable Opinion