Treating stroke
===============

* Richard Verbeek

Alastair Buchan and Thomas Feasby champion thrombolysis for patients experiencing acute ischemic stroke.1 In their enthusiasm, they advocate prehospital triage of patients by emergency medical service (EMS) personnel to designated urban stroke centres. For this to work, triage guidelines must allow accurate identification of candidates for thrombolysis. Unfortunately, such guidelines do not exist. The sensitivity of the most widely published prehospital guideline for identifying stroke, when used by paramedics, is only 59%.2 This means that for every 10 patients triaged as having had a stroke, 7 patients with stroke would not be recognized as requiring triage to a stroke centre.

Since the prevalence of stroke in prehospital patients is as low as 0.4%,3 any triage rule is bound to have an extremely low positive predictive value. This would remain true even if the prevalence of stroke in these patients were as high as 10%. Therefore, triage rules may result in preferential transport of large numbers of patients without stroke to stroke centres.4 Many of these patients will have other serious medical conditions3 requiring admission by a non-neurology service. Lastly, no triage rule can address the needs of patients who arrive by private transport, or have a stroke as an inpatient, at a hospital that is not a stroke centre.

A more appropriate urban EMS system design is to use stroke guidelines as a means of rapid stroke identification, not triage. Identified patients would receive high-priority transport, with advanced notification of the nearest hospital that must be "stroke ready" in any event. Once treatment was given, the EMS system could rapidly respond to initiate patient transport to a designated stroke centre for ongoing care.

Buchan and Feasby suggest that even rural centres be prepared to deliver thrombolytic therapy to acute stroke patients. There is no reason why all urban centres should not be prepared as well.

## References

1.  1. Buchan AM, Feasby TE. Stroke thrombolysis: Is tissue plasminogen activator a defibrillator for the brain? CMAJ 2000;162(1):47-8.
    
    [FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiRlVMTCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiY21haiI7czo1OiJyZXNpZCI7czo4OiIxNjIvMS80NyI7czo0OiJhdG9tIjtzOjIzOiIvY21hai8xNjIvOS8xMjczLjEuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

2.  2. Kothari RU, Pancioli A, Liu T, Brott T, Broderick J. Cincinnati prehospital stroke scale: reproducibility and validity. Ann Emerg Med 1999;33:373-8.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1016/S0196-0644(99)70299-4&link_type=DOI) 
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=10092713&link_type=MED&atom=%2Fcmaj%2F162%2F9%2F1273.1.atom) 
    
    [Web of Science](http://www.cmaj.ca/lookup/external-ref?access_num=000079433500001&link_type=ISI) 

3.  3. Smith WS, Isaacs M, Corry MD. Accuracy of paramedic identification of stroke and transient ischemic attack in the field. Prebospital Emerg Care 1998;2:170-5.
    
    

4.  4. Verbeek PR, Schwartz B. Prehospital triage to stroke centres: Is it a solution to the problem? CJEM 2000;2(2):106-80.