Methodology: 4/5
Usefulness: 4/5

Perry JJ, et al. Stroke. 2020 Feb;51(2):424-430. doi: 10.1161/STROKEAHA.119.026969.

Question and Methods: Prospective, multi-center before and after study looking at the implementation of the Ottawa Subarachnoid Hemorrhage Rule and 6-Hour CT Rule.
Findings: Implementation of the Ottawa SAH Rule did not affect the rate of CT ordering. Implementation of the 6-Hour CT rule decreased testing beyond initial CT. Both rules were highly sensitive.
Limitations: Many clinicians were using the rules in the control phase. Unlike prior studies, there was no telephone follow-up.

Interpretation: The Ottawa SAH Rule and 6-Hour CT rule are highly sensitive and may help to standardize the ED work-up of SAH. 

By: Dr. Michael Hale


  • Hans Rosenberg

    Dr. Rosenberg is an emergency physician at the Ottawa Hospital, assistant professor at the University of Ottawa, and Director of the Digital Scholarship and Knowledge Dissemination Program.