Ottawa SAH clinical decision rule helps identify subarachnoid hemorrhage
BY MARY ANN MOON
From JAMA
A new clinical decision rule had sensitivity and specificity approaching 100% in ruling out subarachnoid hemorrhage among patients who presented to an emergency department with acute headache, a validation study showed.
Using this new tool, which requires only that the clinician answer six simple questions regarding the patient’s presentation, has the potential to reduce the number of costly and sometimes invasive procedures that are currently relied on to distinguish subarachnoid hemorrhage (SAH) from other pathologies, said Dr Jeffrey J. Perry of the department of emergency medicine at the University of Ottawa (Ont.) and the clinical epidemiology program at the Ottawa Hospital Research Institute and his associates.
Dr Perry and his colleagues devised three clinical decision rules to assist in ruling out SAH, then assessed the three rules for their accuracy, reliability, and acceptability to clinicians in a validation cohort of consecutive patients aged 16 years and older who presented to an ED with a nontraumatic headache that reached maximal intensity within 1 hour. There were 2,131 study subjects with a mean age of 44 years. Approximately 61% were women, and 26% arrived at the ED by ambulance.
All of these participants were treated by attending physicians certified in emergency medicine or by supervised residents at 10 university-affiliated urban, Canadian tertiary care teaching hospitals during a 4-year period. All patients were alert and oriented, with no neurologic deficits; 132 (6.2%) were found to have SAH.
After comparing the performances of the three candidate decision rules, the investigators refined the decision tool to identify six factors that were most predictive of SAH: age of 40 years or older, neck pain or stiffness, witnessed loss of consciousness, onset of headache during exertion, "thunderclap headache" (defined as instantly peaking pain), and limited neck flexion (defined as the inability to touch chin to chest when upright or to raise the head 8 cm off the bed when supine).
The presence of any one of these six factors indicates that SAH is possible and further investigation is required using CT and perhaps lumbar puncture, Dr Perry and his associates said.
This refined clinical decision rule, which they termed the Ottawa SAH rule, had an overall sensitivity of 99.2% and a specificity of 99.6% in identifying SAHs (JAMA. 2013;310[12]:1248-1255).
Following this rule would decrease the investigation rate"—the rate of further assessment using CT and lumbar puncture—"to 74% from the current investigation rate of 84%, the researchers added.
The Ottawa SAH rule must be evaluated further before it can be adopted into clinical practice. "An implementation study is the next step required to determine how the Ottawa SAH rule performs in clinical practice, assess the actual effects on patient care and patient outcomes, and conduct a formal health economic analysis," the researchers noted.
This study was supported by the Canadian Institutes for Health Research, the University of Ottawa, and the Vancouver Coastal Health Research Institute. No financial conflicts of interest were reported.
Novel two-biomarker strategy permits early ACS rule-out
BY BRUCE JANCIN
At the ESC Congress 2013
AMSTERDAM—An early rule-out strategy based upon using two cardiac biomarkers allowed for safe discharge within a couple hours from the emergency department for most low- to intermediate-risk patients who presented with suspected acute coronary syndromes, based on the results of a randomized, multicenter trial conducted in Europe.
Moreover, the 30-day rates of major adverse cardiovascular events in the Biomarkers in Cardiology–8 (BiC-8) study were similarly low in patients discharged from the ED using the early rule-out process and in those who received standard, guideline-recommended care, which includes 6-12 hours of serial ECGs and troponin measurements in the chest pain unit, Dr Martin Moeckel reported at the annual congress of the European Society of Cardiology.
"This biomarker strategy using a state-of-the-art quantitative troponin assay in combination with an ultrasensitive copeptin assay has the potential to change clinical practice with high patient safety," observed Dr Moeckel of Charite Hospital, Berlin. The copeptin test is approved for use in the European Union but remains investigational in the United States.
Based upon the results of BiC-8, this dual-biomarker for early rule-out of myocardial infarction is now standard clinical practice at Charite, he added.
Nearly 12% of all patients who present to the ED do so because of chest pain, yet after an extensive and time-consuming evaluation only 1 in 10 of those patients are found to actually be having an acute MI.
"Rapid rule-out of acute MI is therefore a major clinical need, saving the health care system time and resources, and saving patients unnecessary stress, anxiety, and other risks," he said.