Will treatment window for stroke in the ED widen?
Will treatment window for stroke in the ED widen?
Does every stroke patient who comes to your ED and is eligible for treatment with clot-busting drugs receive potentially life-saving medication? The answer is almost definitely no. Only about 2% of strokes are treated with thrombolytic therapy in the United States currently.1
"That is partly due to resistance to getting the therapy on board, predominately from ED physicians who are concerned about the potential for hemorrhage," says Michael Sharma, MD, a researcher at the Agency for Healthcare Research and Quality’s (AHRQ’s) University of Ottawa Evidence-based Practice Center and director of the regional stroke program at the Ottawa Hospitals.
This is mainly due to lack of familiarity with the amount of research that has accumulated since the 1995 National Institute of Neurological Disorders and Stroke study showing the effectiveness of tissue plasminogen activator (t-PA) for acute ischemic stroke, he explains.
"There are now meta-analyses from five trials that suggest the hemorrhage rate was 6% or even less, with well-established protocols," he says. Now a new evidence report from AHRQ on the effectiveness of various methods of treating hemorrhagic and ischemic stroke within 24 hours of onset of symptoms gives additional support to the effectiveness of t-PA.
The report, Acute Stroke, Evaluation and Treatment, developed by AHRQ’s University of Ottawa Evidence-based Practice Center, says that intravenous treatment with t-PA not only is effective for acute ischemic stroke if given within three hours of symptom onset, but there also may be benefits beyond this three-hour window.
The report underscores that acute stroke treatment is very time-dependent, says Sharma. "Minutes count in determining the patient’s outcome," he adds. "The second very important thing is even when you take the hemorrhage rate into account, outcomes are better with treatment. Your chance of being free of disability is still better than if untreated."
The effectiveness of t-PA is strongly linked to time, since onset of symptoms with shorter times demonstrate significantly better outcomes. "There is definitely evidence that some patients benefit beyond three hours," says Sharma. "For some patients, the potential for treatment can be up to six hours. So it becomes very important to identify those patients."
Computed tomography (CT) scans or magnetic resonance imaging is used to locate an area of the brain that is deprived of blood flow but not yet dead, he explains. "The neurons stop working but it takes hours for them to die. If you can re-establish blood flow, you can prevent the disabilities that accompany stroke," says Sharma.
Here are other key findings of the report:
• For patients with intracerebral hemorrhage (ICH), data suggest that surgery tends to lower the mortality rate in severely affected patients but doesn’t improve outcome in less severe cases. "No study offered a definitive role for the control of hypertension in ICH," says Dawn K. Beland, RN, MSN, CCRN, CS, CNRN, coordinator at the Stroke Center at Hartford (CT) Hospital. "Practice guidelines, however, suggest that maintaining a systolic blood pressure less than 160 mmHg will lower the risk of hematoma enlargement."
• While no studies have shown benefit of tight glycemic control, there also have been no studies demonstrating harm. "Overwhelmingly, data suggest that aggressive glycemic control should be the standard of care," says Beland.
• The object of intra-arterial thrombolysis, or even of mechanical embolectomy, is to restore blood flow. "If blood flow can not be restored spontaneously or with the use of intravenous thrombolytic, disability or death is certain," says Beland. "The report says, The possibility of substantial benefit from intra-arterial therapy cannot be excluded.’"
• The use of transcranial dopplers or ultrasound enhancement of thrombolysis is a new, noninvasive method to restore cerebral blood flow. "While this method still needs to gather additional supportive data, it will provide a palatable alternative to other more aggressive measures," says Beland.
ED stroke protocols and coordinated stroke-designated centers can decrease the time to treatment and increase the number of treated patients, says Beland. "Despite the variety in ED stroke protocols, any attempt to organize and efficiently structure the care provided to acute stroke patients will help to improve the outcome for that patient."
The Ottawa Hospital treats 20% of stroke patients with thrombolytic therapy, which is up from 2.8% before a stroke team was implemented. Sharma attributes the success to education of the community, pre-hospital providers, and ED staff. "We trained ED staff from triage onward to have a written protocol and call the team as soon as stroke is recognized," he says. "It’s important to get people involved who you might not think about very much." These people include patient transporters, laboratory and CT techs, and the staff person who pages the stroke team.
"ED nurses are critical," adds Sharma. "I would go so far as to say that if you don’t have ED nurses on board as enthusiastic supporters, you are guaranteed to fail."
Reference
- Marler JR, Goldstein LB. Stroke: tPA and the clinic. Science 2003; 301:1,677.
Sources/Resource
For more information on stroke treatment in the ED, contact:
- Dawn K. Beland, RN, MSN, CCRN, CS, CNRN, Stroke Center Coordinator, The Stroke Center at Hartford Hospital, 80 Seymour St., Hartford, CT 06102-5037. Telephone: (860) 545-2183, ext. 5. Fax: (860) 545-1976. E-mail: [email protected].
- Mike Sharma, MD, Director, Regional Stroke Program, The Ottawa Hospital, General Campus, 501 Smyth Road, Ottawa, Ontario, Canada. Telephone: (613) 737-8798. Fax: (613) 737-8857. E-mail: [email protected].
- To access the Agency for Healthcare Research and Quality’s evidence report on-line, go to www.ahrq.gov. Under "Clinical Information," click on "Evidence-based practice," "List of Reports by Number," and scroll down to No. 127 and click on "Acute Stroke: Evaluation and Treatment." Or a single copy of the full report is available at no charge by sending an e-mail to [email protected].
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