In a paper presented at the 2006 Society for Academic Emergency Medicine Annual Meeting, May 18-21, 2006 in San Francisco, a group of Canadian researchers reported on their investigation of a protocol which could minimize invasive testing. In a study conducted at 6 university Emergency Departments involving nearly 2000 patients, 80% underwent head computed tomography (CT), 45% received lumbar puncture (LP, i.e. a spinal tap), 83% had either CT and/or LP, and 6.4% had a final diagnosis of SAH.
By using 4 simple clinical observations, the authors were able to predict whether a patient was at high risk for SAH. For example, of those who arrived by ambulance, 57% were later diagnosed with SAH, while only 17% of those who arrived by ambulance did not have SAH. Vomiting was a symptom in 58% of the patients with SAH and only in 26% of those without SAH. A diastolic blood pressure "100mmHg or age 45" were also strong predictors of SAH.
By using these simple observations, the authors developed a clinical rule that any patient showing 1 or more of these symptoms would then be a candidate for further investigation, via CT and/or LP. This rule would identify all the patients with SAH, while reducing the investigation rate to 66%.
According to Jeffrey Perry, MD, "While we do not recommend an immediate change in management until after a validation study is complete, this study will have a tremendous impact on patient care. It will improve our ability to determine which patients require investigations for their headache and which ones just need pain control without costly and invasive testing."
The presentation is "A Clinical Decision Rule to Safely Rule-Out Subarachnoid Hemorrhage in Acute Headache Patients in the Emergency Department" by Jeffrey J Perry MD. Dr. Perry's co-authors are Ian G Stiell MD, George A Wells PhD, Melodie Mortensen RN, Marco Sivilotti MD, Michael Bullard MD, Cheryl Symington RN, Howard Lesiuk MD, Jacques S Lee MD, Mary A Eisenhauer MD, Lorne Wiesenfeld MD, and Joseph Caytak MD. Dr. Perry is an emergency medicine physician at The Ottawa Hospital, a scientist at the Ottawa Health Research Institute, and an assistant professor at the University of Ottawa.
This paper will be presented at the 2006 SAEM Annual Meeting, May 18-21, 2006, San Francisco, CA on Thursday, May 18, in the Plenary Session beginning at 8:00 AM in Salon 9 of the San Francisco Marriott. Abstracts of the papers presented are published in the May issue of the official journal of the SAEM, Academic Emergency Medicine.