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Currently accepted at: JMIR mHealth and uHealth

Date Submitted: Jul 15, 2019
Open Peer Review Period: Jul 18, 2019 - Sep 9, 2019
Date Accepted: Sep 23, 2019
(closed for review but you can still tweet)

This paper has been accepted and is currently in production.

It will appear shortly on 10.2196/15503

The final accepted version (not copyedited yet) is in this tab.

The addition of the Canadian CT Head Rule, Transient Ischemic Attack Score and Subarachnoid Hemorrhage Rule to The Ottawa Rules App

  • Amanda My Linh Quan; 
  • Ian Stiell; 
  • Jeffrey J. Perry; 
  • Michelle Paradis; 
  • Erica Brown; 
  • Jordan Gignac; 
  • Lindsay Wilson; 
  • Kumanan Wilson; 



The Canadian CT Head Rule (CCHR), the Canadian Transient Ischemic Attack (TIA) Score and Subarachnoid Hemorrhage (SAH) Rule have all previously demonstrated the potential to significantly standardise care and improve the management of patients in EDs. Based on user feedback, we believe the addition of these rules to The Ottawa Rules App has the potential to increase the app’s usability and user acceptability.


The primary objective of this study was to evaluate the perceived usefulness, acceptability and uptake of the enhanced The Ottawa Rules App (now includes CCHR, TIA and SAH Rules) among ED clinicians (Medical Students, Residents, Nurses and Physicians).


The enhanced The Ottawa Rules App was publicly released for free on iOS and Android operating systems in November 2018. This study was conducted across two tertiary EDs in Ottawa, Canada. Posters, direct enrolment, snowball sampling and emails were used for study recruitment. A 24-question online survey was administered to participants via email, and was used to determine user acceptability of the app and Technology Readiness Index (TRI) scores. In-app user analytics were collected to track user behavior such as number of app sessions, length of app sessions, frequency of rule use, date app was first opened etc.


A total of 77 ED clinicians completed the study including 34 nurses, 12 residents, 14 physicians, and 17 medical students completing ED rotations. The median TRI score for this group was 3.38, indicating a higher than average propensity to embrace/adopt new technologies to accomplish goals in their work or daily lives. The majority of respondents agreed or strongly agreed that the app helped participants accurately carry out the clinical rules (56/77,72.7%), and that they would recommend this app to their colleagues (64/77, 83.1%). Feedback from study participants suggested further expansion of the app - more clinical decision rules, and different versions of the app tailored to clinician role. Analysis and comparison of Google Analytics data and in-app data revealed similar usage behavior among study enrolled users and all app users globally.


This study provides evidence that the use of The Ottawa Rules App (Version 3.0.2) to improve and guide patient care would be feasible and widely accepted. The ability to verify self-reported user data (via online survey) against server analytics data is a notable strength of this study. Participants’ continued app use and request for the addition of more CDRs warrants the further development of this app and call for additional studies to evaluate its feasibility and usability in different settings as well as assessment of clinical impact.


Please cite as:

Quan AML, Stiell I, Perry JJ, Paradis M, Brown E, Gignac J, Wilson L, Wilson K

The addition of the Canadian CT Head Rule, Transient Ischemic Attack Score and Subarachnoid Hemorrhage Rule to The Ottawa Rules App

JMIR mHealth and uHealth. (forthcoming/in press)

DOI: 10.2196/preprints.15503


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