Acute ischemic STROKE:

Transcription

1 Acute ischemic STROKE: Familiarize yourself with recommendations from the latest stroke care guidelines so you ll be prepared to respond within the narrow therapeutic window for optimal treatment. By Julie Miller, BSN, RN, CCRN, and Janice Mink, RN, CCRN, CNRN Rita Smith, 67, has suddenly become unable to speak and move her right arm and leg. Her husband calls 911 and describes her signs and symptoms. The dispatcher activates the emergency medical service (EMS) system for a patient with an acute stroke. What s next? On arrival, the EMS personnel find Ms. Smith awake and alert with intact ABCs (airway, breathing, and circulation) but note right-sided hemiplegia, a right facial droop, and expressive aphasia. In this article, we ll review guidelines for acute ischemic stroke care for adults, based on the most recent revisions. 1 (See Improving response improves outcomes.) We ll also walk you through Ms. Smith s care based on these guidelines. But first, let s look at the two types of strokes. Sorting out strokes About 87% of strokes are ischemic, meaning they result from impaired blood flow and oxygen supply to a localized area of the brain. Cerebral hypoperfusion can result from thrombosis, atherogenic plaque, or embolism, most commonly cardiogenic embolism as from atrial fibrillation. In contrast, hemorrhagic strokes, representing 13% of all strokes, are caused by a rupture of a blood vessel and include intracerebral hemorrhage and subarachnoid hemorrhage. 2 Treating hemorrhagic stroke is beyond the scope of this article. Now let s consider the guidelines. Using seven D s to evaluate the patient The American Heart Association (AHA) has developed the seven D s of stroke care, a mnemonic device that helps the stroke team evaluate the patient s condition quickly and determine if she s a candidate for fibrinolytic therapy. Alteplase recombinant tissue plasminogen activator (rtpa) is the only fibrinolytic agent approved for acute ischemic stroke Detection: Early recognition of stroke signs and symptoms and determination of onset time. Education of the public is crucial for early detection. 2. Dispatch: EMS activation and rapid intervention 3. Delivery: Advanced prehospital notification and transport to the nearest facility offering acute stroke care 4. Door: Rapid triage in the ED, giving the same high priority as for an acute myocardial infarction ILLUSTRATION BY ROY SCOTT 40 l Nursing2010Critical Care l Volume 5, Number 1

2

3 Acute ischemic stroke or serious trauma regardless of the severity of stroke signs and symptoms 5. Data: History, neurologic assessment, and diagnostic testing, including a stat noncontrast computed tomography (CT) or magnetic resonance imaging (MRI) scan performed within 25 minutes of arrival and read within 45 minutes of arrival 6. Decision: Evaluation of inclusion and exclusion criteria for rtpa. Inclusion criteria include age 18 years or older, a clinical diagnosis of acute ischemic stroke with a measurable neurologic defect, and time of symptom onset less than 180 minutes (3 hours) before fibrinolytic therapy would begin. All three of these inclusion criteria must be met before rtpa can be administered. In addition, all of these exclusion criteria (absolute contraindications) must be absent for the patient to be considered a candidate for fibrinolytic therapy: history or evidence of intracranial hemorrhage evidence of multilobar infarction on CT scan clinical presentation suggestive of subarachnoid hemorrhage Improving response improves outcomes In 1996, the original AHA guidelines for use of rtpa, a fibrinolytic agent, were approved to treat acute ischemic stroke. Since then, transport, community awareness of acute stroke signs and symptoms, and treatment have improved immensely. Research shows that most stroke patients now arrive at hospitals within 3 hours of symptom onset and that more than half of these patients are transported via emergency medical transport. 1 Treating acute ischemic stroke with I.V. rtpa within 3 hours of stroke onset dramatically reduces deaths and disabilities. Recent advances in intra-arterial fibrinolysis and endovascular thrombus retrieval devices allow for effective intervention in some acute ischemic stroke patients who arrive up to 8 hours after onset of symptoms. Alteplase recombinant tissue plasminogen activator (rtpa) is currently the only fibrinolytic agent approved for acute ischemic stroke. known arteriovenous malformation, neoplasm, or aneurysm systolic BP greater than 185 mm Hg or diastolic BP greater than 110 mm Hg despite repeated measurements and treatment seizure with postictal residual neurologic impairment acute bleeding tendencies such as a platelet count less than 100,000/mm 3, a prothrombin time (PT) greater than 15 seconds or international normalized ratio (INR) greater than 1.7, or activated partial thromboplastin time (aptt) greater than the upper limit of normal active internal bleeding or acute trauma such as fracture serious head trauma, stroke, or intracranial or intraspinal surgery in the previous 3 months arterial puncture at a noncompressible site within 1 week. Besides these inclusion and exclusion criteria, relative contraindications (or precautions) should be considered before fibrinolytic therapy, including: postmyocardial infarction pericarditis only minor or rapidly improving stroke symptoms abnormal blood glucose (less than 50 or greater than 400 mg/dl) major surgery or serious trauma within 14 days recent acute myocardial infarction (within previous 3 months) recent gastrointestinal or urinary tract hemorrhage (within previous 21 days) Drug: Initiation of weight-based rtpa within 3 hours of symptom onset if patient meets all inclusion criteria and has no exclusion criteria. The AHA s algorithm for suspected stroke has time frame guides to help the stroke team collect data. 3 If you re part of the stroke team, proceed as follows. In the first 10 minutes after ED arrival: Alert the stroke team. Assess your patient s ABCs and vital signs. Is her airway patent? Is she breathing? Does she have a pulse? What s her respiratory rate and is she using accessory muscles of respiration? Do her skin color and temperature and capillary refill time indicate compromised circulation? Can she effectively clear 42 l Nursing2010Critical Care l Volume 5, Number 1

4 Using a stroke assessment tool The NIHSS offers alternative assessment tools for patients with language and motor difficulties. See the NIHSS at nihss.html for complete directions on administering and scoring it. Administer the stroke scale in this order: level of consciousness gaze visual fields facial movement motor function of arms and legs limb ataxia sensory responses language articulation extinction and inattention A score greater than 22 indicates that the patient has a high risk of hemorrhage, requiring caution in the decision to use rtpa. The recommendation is to administer the NIHSS every 12 hours for the first 24 hours, then every 24 hours until discharge. Check your facility s stroke protocol for time frames. The NIHSS must be administered the same way each time it s performed, so all NIHSS evaluators should undergo the same training to ensure accuracy, reliability, and validity of the score. If you and other team members need training on how to administer the NIHSS, the American Stroke Association offers free training with certification testing at strokeassociation.org/presenter.jhtml?identifier= How stroke centers compare The Brain Attack Coalition published recommendations in 2000 advocating for the implementation of primary stroke centers and, more recently, comprehensive stroke centers. A primary stroke center has the essential components to manage uncomplicated strokes: expert personnel, protocols, infrastructure, and capacity to admit patients into a stroke unit. 1 Early evidence shows that patients with acute ischemic stroke treated at a primary stroke center are more likely to receive fibrinolytic agents. 1 Comprehensive stroke centers not only fulfill the requirements for a primary stroke center, but they also provide diagnostic services such as MRI and interventional neuroradiology for endovascular treatments. In 2004, The Joint Commission began certifying primary stroke centers and is currently working with the American Stroke Association on certification for comprehensive stroke centers. 7 The guidelines recommend transporting a patient suspected of having a stroke to the closest, most appropriate facility. 1 This means that EMS should bypass facilities that don t have the resources or institutional commitment to treat a patient with stroke if a facility with the proper resources is reasonably close. secretions? Stroke can impair the swallow, cough, and gag reflexes, so maintain strict N.P.O. status until she s formally evaluated for aspiration risk. Provide supplemental oxygen to maintain oxygen saturation at 92% or greater. Establish or confirm venous access. Patients who are fibrinolytic candidates should have two largebore venous access devices, with one dedicated for fibrinolytic therapy. Infuse 0.9% sodium chloride solution to maintain eu volemia, making sure to avoid excessive fluid loading. Don t administer D5W or any other glucose-containing solution because it can contribute to cerebral edema and lactic acidosis. 1,2 Obtain blood specimens for baseline lab tests, including glucose, electrolytes, complete blood cell (CBC) count with platelet count, PT, INR, aptt, cardiac biomarkers, and renal function studies. Treat abnormal blood glucose levels if necessary to maintain a normal glucose level. Prevent hyperglycemia, which has been associated with poor outcomes, and hypoglycemia, which can mimic signs and symptoms of a stroke. Ensure the healthcare provider s order for the CT scan is communicated to the radiology department so they ll be ready when you arrive with the patient. Obtain a 12-lead ECG and attach the patient to a cardiac monitor. Perform a neurologic screening assessment, such as screening with the Cincinnati Prehospital Stroke Scale. Within 25 minutes of arrival: Establish or confirm the time of stroke symptom onset and review the patient s history. Time of onset is considered to be the last time the patient was known to be normal without stroke signs and symptoms. If she awakened with signs and symptoms of a stroke, the onset time is the last time she was seen awake without them. Perform a neurologic exam using the National Institutes of Health Stroke Scale (NIHSS) to evaluate the severity of Ms. Smith s stroke. 5,6 See Using a stroke assessment tool for details. Perform a focused physical assessment. Treat temperature if greater than 37.5 C (99.5 F). Hyperthermia in patients January l Nursing2010Critical Care l 43

5 Acute ischemic stroke with acute cerebral ischemia is associated with increased morbidity and mortality. 1 Ensure that the noncontrast CT scan or MRI has been started. 3 A CT scan is the usual choice because it s more widely available than MRI. In most cases, use of contrast media isn t recommended because it won t provide additional information and may be associated with adverse reactions. Imaging results must be read within 45 minutes of the patient s arrival by a practitioner skilled in CT or MRI interpretation. To illustrate the guidelines in practice, let s follow Ms. Smith s case. The EMS personnel immediately transport the patient to the closest facility equipped to provide emergency stroke care (see How stroke centers compare), calling ahead so the stroke team will be ready to assess Ms. Smith and diagnose her condition as soon as she arrives. Acute ischemic stroke must be rapidly differentiated from hemorrhagic stroke to guide treatment decisions. Administration of rtpa is the most effective treatment for acute ischemic stroke when administered within 3 hours of stroke onset. But evidence of intracranial hemorrhage on pretreatment noncontrast head CT is an absolute contraindication for the use of I.V. fibrinolytic therapy. When Ms. Smith arrives at the hospital, the stroke team s priorities are to diagnose acute ischemic stroke, rule out hemorrhagic stroke and any other contraindications to rtpa, and begin fibrinolytic therapy within the 3-hour therapeutic window. In Ms. Smith s case, the first two D s, Detection and Dispatch, have already been performed by EMS. Delivery and Door occurred when the EMS delivered Ms. Smith to the door of a primary stroke center. Activation of the hospital s stroke team occurred during Ms. Smith s transport. Alerted ahead of time, the stroke team begins data collection as soon as she arrives at the ED door. The stroke team consists of a neurologist, radiologist, CT technologist, stroke coordinator, nurses, Urge clinicians to fully explain the benefits and potential risks of treatment to the patient and her family, if possible and others designated to respond to the patient s arrival. Members of a core stroke team must complete 8 hours of stroke education for primary stroke center certification by The Joint Commission. 7 Knowing the time of symptom onset will be crucial for determining appropriate treatment. When you ask Mr. Smith exactly when he first noticed something was wrong with his wife, he said it was just after breakfast, at about 0900, so based on the AHA guidelines, rtpa should be started by 12 noon. Ms. Smith s initial NIHSS score is 20. She takes medication for hypertension and dyslipidemia. Deciding on treatment Decision is the sixth D. BP is a key assessment criterion for use of rtpa. Using rtpa is contraindicated if the patient s systolic BP remains greater than 185 mm Hg or her diastolic BP remains greater than 110 mm Hg at the time fibrinolytic therapy should begin despite repeated BP measurements and pharmacologic therapy. These higher pressures increase the risk of intracerebral hemorrhage, the most serious adverse reaction associated with rtpa. Ms. Smith s vital signs are heart rate, 98; BP, 190/78; respiratory rate, 18; and temperature, 98.2 F. Her elevated systolic BP must be treated before fibrinolytic therapy can be started. She can be treated with either I.V. labetalol, nitropaste, or nicardipine infusion as per AHA guidelines. Ms. Smith s healthcare provider orders a onetime dose of I.V. labetalol over 2 minutes. On recheck, her BP is down to 172/78. Her CT scan results show no evidence of intracranial hemorrhage. Ms. Smith meets all the inclusion criteria, and now with her BP under control, she has no contraindications for rtpa administration. The guidelines say that written consent isn t necessary before rtpa administration, but urge clinicians to fully explain the benefits and potential risks of treatment to the patient and her family if possible. 1 Ms. Smith s healthcare provider discusses the 44 l Nursing2010Critical Care l Volume 5, Number 1

6 pros and cons of rtpa therapy with her and her husband, and Ms. Smith consents to treatment. It s now Major sites and sources related to ischemic stroke Administering rtpa The rtpa dosage for acute ischemic stroke is weight based, so obtain an accurate patient weight. Ten percent of Ms. Smith s total dose will be administered as an initial bolus over 60 seconds, and the remaining 90% is infused over the next hour. 1 Once you ve administered the bolus dose and started the infusion, monitor her BP and neurologic status every 15 minutes during therapy and for 2 hours after therapy, then every 30 minutes for 6 hours, and then every hour for 16 hours. 1 You ll need to manually obtain her BP for the first 24 hours to avoid tissue damage associated with automatic noninvasive BP monitors. 1,8 Sites of large artery and small penetrating artery thromboses Sources of cardiogenic emboli During and after rtpa administration, the risk of hemorrhage is higher if systolic BP is 180 or greater, or diastolic BP is 105 or greater. These BP parameters are lower than the pre rtpa parameters because the risk of intracerebral hemorrhage increases during and after rtpa administration. So during and after the infusion, Ms. Smith s BP must be managed with antihypertensive medication, if necessary, to keep it below 180/105. Forty-five minutes into the infusion, Ms. Smith s BP is 196/90. To lower her systolic BP, the healthcare provider orders a repeat dose of I.V. labetalol over 1 to 2 minutes. Shortly after administration, Ms. Smith s BP is 176/88, and it remains below 180/105 in subsequent measurements. The guidelines warn clinicians to lower BP conservatively no more than 15% to 25% in the first day because aggressive treatment of BP may lead to neurologic worsening by reducing perfusion pressure to ischemic areas of the brain. 1 Sodium Intracranial atherosclerosis Carotid plaque with arteriogenic emboli Aortic arch plaque Cardiogenic emboli Penetrating artery disease Flow reducing carotid stenosis Atrial fibrillation Valve disease Left ventricular thrombi Source: Hickey JV. The Clinical Practice of Neurological and Neurosurgical Nursing. 6th ed. Philadelphia, Pa.: Lippincott Williams & Wilkins; nitroprusside is the only drug recommended by the guidelines for treating hypertension not controlled by either labetalol or nicardipine. During and following the rtpa infusion, assess neurologic status and vital signs for early indications of recovery and for bleeding. Anticoagulants and antiplatelet agents are contraindicated in the first 24 hours following rtpa administration for acute ischemic stroke. Signs and symptoms that may indicate bleed - ing include changes in vital signs (tachycardia, hypotension, tachypnea), change in mental status, headache, nausea, vomiting, or visual changes. Assess for any signs of internal bleeding, such as intracranial or gastrointestinal bleeding, or superficial bleeding, such as from venipuncture sites. Alert the primary care provider and neurologist, and perform the NIHSS again. If the neurologist suspects intracranial bleeding, he ll order a stat CT scan of the brain along with a coagulation profile, CBC count, platelet count, January l Nursing2010Critical Care l 45

7 Acute ischemic stroke fibrinogen, and type and cross. A decision to treat medically or surgically will be made. Be ready to administer cryoprecipitate or fresh frozen plasma if hemorrhage is identified on the CT scan. 9 Following rtpa administration, the patient should be admitted to an ICU or stroke unit for close monitoring. 1 Ms. Smith is transferred to the neurologic ICU. Her posttreatment 12-hour NIHSS score has decreased to 7 (from 20) with sensory and motor loss in her arm and mild aphasia. Her BP has remained stable. Other treatment options The guidelines offer recommendations for treatment options that may help patients who are admitted beyond the 3-hour therapeutic window for rtpa. These options are available at facilities functioning as comprehensive stroke centers. Catheter-directed intra-arterial fibrinolysis, which involves delivery of a highly concentrated fibrinolytic agent directly into the thrombus, may be possible up to 6 hours after the time of stroke onset for patients who aren t otherwise candidates for I.V. rtpa. Inclusion criteria are the same as for I.V. rtpa with the addition of angiographic evidence of thrombus. Exclusion criteria vary based on clinical trials or facility protocols. Currently, no fibrinolytic has received FDA approval for intra-arterial fibrinolysis. 10 For patients who aren t candidates for fibrinolytic therapy, endovascular mechanical embolectomy may be an option. This procedure may be performed up to 8 hours after stroke onset. 11 Special care in special unit Ms. Smith is prepared for transfer to the specialized stroke unit after being monitored for 24 hours in the ICU. Physical and speech rehabilitation begin. Because she doesn t pass the bedside dysphagia screening, a swallowing evaluation is scheduled. She remains N.P.O. so a feeding tube is inserted 24 hours after rtpa administration and a dietician coordinates planning for enteral nutrition. Keep up with advances Advances in stroke care continue to improve outcomes for patients. As you provide nursing care, you can contribute to better outcomes with astute assessments and interventions based on the best evidence to date. Work to educate your patients and the public about the signs and symptoms of stroke. Promptly activating the EMS system is the key to a good outcome for a patient having a stroke. REFERENCES 1. Adams HP Jr, del Zoppo G, Alberts MJ, et al. Guidelines for the early management of adults with ischemic stroke: a guideline from the American Heart Association/American Stroke Association Stroke Council, Clinical Cardiology Council, Cardiovascular Radiology and Intervention Council, and the Atherosclerotic Peripheral Vascular Disease and Quality of Care Outcomes in Research Interdisciplinary Working Groups. Stroke. 2007;38(5): ahajournals.org/cgi/content/full/38/5/ Hickey JV. The Clinical Practice of Neurological and Neurosurgical Nursing. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins; Field JM, Gonzales L, Hazinski MF, et al. ACLS Provider Manual. Dallas, TX: American Heart Association; Hazinski MF, Field JM, Gilmore D. Handbook of Emergency Cardiovascular Care 2008: For Healthcare Providers. Dallas, TX: American Heart Association; NIH Stroke Scale (NIHSS) training online. strokeassociation.org/presenter.jhtml?identifier= The Internet Stroke Center. Stroke Scales and Clinical Assessment Tools. NIH Stroke Scale (NIHSS). scales/nihss.html. 7. The Joint Commission. Primary Stroke Centers. Primary Stroke Center Certification. Programs/PrimaryStrokeCenters. 8. Burns SM, American Association of Critical-Care Nurses. AACN Protocols for Practice: Noninvasive Monitoring. 2nd ed. Sudbury, MA: Jones and Bartlett; Pugh S, Mathiesen C, Meigham M, Summers D, Zrelak P. Guide to the Care of the Patient with Ischemic Stroke: AANN Clinical Practice Guideline Series. 2nd ed Higashida RT, Furlan AJ, Roberts H, et al.; Technology Assessment Committees of the American Society of Interventional and Therapeutic Neuroradiology and the Society of Interventional Radiology. Trial design and reporting standards for intra-arterial cerebral thrombolysis for acute ischemic stroke. Stroke. 2003;34(8):e109-e Smith WS, Sung G, Starkman S, et al.; MERCI Trial Investigators. Safety and efficacy of mechanical embolectomy in acute ischemic stroke: results of the MERCI Trial. Stroke. 2005;36(7): RESOURCES Concentric Medical. The Merci Retrieval System. concentric-medical.com/webpage.php?ln_id=53. Gordon NF, Gulanick M. Costa F, et al; American Heart Association Council on Clinical Cardiology, Subcommittee on Exercise, Cardiac Rehabilitation, and Prevention; the Council on Cardiovascular Nursing; the Council on Nutrition, Physical Activity, and Metabolism; and the Stroke Council, et al. Physical activity and exercise recommendations for stroke survivors: an American Heart Association scientific statement from the Council on Clinical Cardiology, Subcommittee on Exercise, Cardiac Rehabilitation, and Prevention; the Council on Cardiovascular Nursing; the Council on Nutrition, Physical Activity, and Metabolism; and the Stroke Council. Circulation. 2004;109(16): Smith WS, Sung G, Saver J, et al; Multi MERCI Investigators. Mechanical thrombectomy for acute ischemic stroke: final results of the Multi MERCI trial. Stroke. 2008;39(4): Julie Miller is a staff development educator in critical care and Janice Mink is a staff development educator in neuroscience at Trinity Mother Frances Hospitals and Clinics in Tyler, Tex. 46 l Nursing2010Critical Care l Volume 5, Number 1