Opinion Editorials represent the opinions of the authors and JAMA EDITORIAL and not those of the American Medical Association. The Ottawa Subarachnoid Hemorrhage Rule David E. Newman-Toker, MD, PhD; Jonathan A. Edlow, MD Diagnostic errors lead to death or disability for an estimated rhage and decrease unnecessary, invasive diagnostic testing 150 000 patients in the United States each year. The emer- for patients with low-risk headaches. gency department is a known high-risk location for Is the Ottawa SAH Rule clinically useful? Any test with misdiagnosis. Missed ischemic stroke and brain hemor- near-perfect sensitivity has an intrinsic appeal because a rhage are recognized sources of diagnostic error, with negative result effectively rules out the target disorder. The approximately 9% of cerebrovascular events missed at first rule proposed by Perry et al also has a “rule-out power” or emergency department contact, including an estimated negative likelihood ratio (ie, extent to which the odds of 20% of subarachnoid hemorrhages in patients presenting having a diagnosis will change following a negative test with normal mental status. Because effective treatments result) of 0.024, translating to a 42-fold reduction (ie, 1.0/ are available, diagnostic delays increase morbidity and 0.024) in the likelihood of subarachnoid hemorrhage.
JAMA – American Medical Association
Published: Sep 25, 2013