Category: Critical Care
Keywords: subarachnoid hemmorhage, sah (PubMed Search)
Posted: 11/19/2013 by Feras Khan, MD
(Updated: 11/12/2024)
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Ottawa Rules for Subarachnoid Hemmorhage (SAH)
Background
Design
Results
132 (6.2%) had SAH
Decision rule including any:
Had 98.5% sensitivity (95% CI, 94.6%-99.6%) and 27.5% specificity (95% CI, 25.6%-29.5%)
Adding “thunder-clap” headache and “limited neck flexion on examination” (inability to touch chin to chest or raise the head 8cm off the bed if supine) resulted in 100% (95% CI, 97.2%-100%) sensitivity.
The rule was then evaluated using a bootstrap analysis on old cohort data to validate the rule.
Conclusion/Limitations
For alert patients older than 15 y with new severe nontraumatic headache reaching maximum intensity within 1 h
Not for patients with new neurologic deficits, previous aneurysms, SAH, brain tumors, or history of recurrent headaches (≥3 episodes over the course of ≥6 mo)
Investigate if ≥1 high-risk variables present:
Age ≥40 y
Neck pain or stiffness
Witnessed loss of consciousness
Onset during exertion
Thunderclap headache (instantly peaking pain)
Limited neck flexion on examination