AbstractObjectives & Background
Lone acute sudden headache (LASH) remains a challenging presentation for the emergency physician (EP). Maintaining safe practice and yet balancing the risks and benefits of potential over investigation have generated the development of risk stratification models to help identify patients with serious pathology such as subarachnoid haemorrhage SAH). The Ottawa SAH rule has potential to reduce the need for radiological intervention and lumbar puncture in certain groups of patients but has not been validated in a UK setting.Objectives & Background
To validate the Ottawa SAH rules in a UK emergency setting and assess its potential performance.Methods
A structured data retrieval tool was developed to perform a retrospective medical record review for all patients admitted to the Clinical Decision Units of two Emergency Departments (EDs) with severe headache, over a 12 month period. The Ottawa (OSAH) rules were then applied to this data set.Results
Of the 1096 patients recruited to the study, 890(81.2%) had a CT scan performed due to a consideration of LASH to exclude SAH. Of patients with a normal CT, only 346 had a lumbar puncture (LP) performed due to patient choice or clinician decision making. A total of 15 patients had SAH confirmed (1.37%) – all on non contrast CT. Applying the OSAH rules would have identified all 15 patients with SAH (100% sensitivity). There was also the potential to decrease the number of LPs performed by 27%, 37% and 44% for each clinical risk tool.Conclusion
The OSAH rule is a useful adjunct to clinical decision making in patients presenting to ED with LASH in a UK population. The EP can also use data from studies like ours (the largest single centre study in the UK to date) to help in joint decision making with patients to help quantify risk and appropriateness of need for further investigation.