高血压英文ppt精品课件cerebrovascular

Cerebrovascular Stroke bdul-Monim BatihaADr. Assistant Professor Critical Care Nursing Cerebrovascular disease is the most frequent neurological disorder of adults. It is the third leading cause of morbidity and mortality in the USA after heart disease and cancer. It includes any pathological process that involves the blood vessels of the brain. Most cerebrovascular disease is caused by thrombosis, embolism, or hemorrhage. The mechanism of each of these etiologies is different, but the ultimate result is damage to a focal area of the brain. A “brain attack” must be viewed as a medical emergency. To reverse cerebral ischemia, patients must be evaluated promptly. Ischemic brain injury occurs when arterial occlusion lasts longer than 2 to 3 hours. Delay in seeking medical care may eliminate the potential for tissue- saving therapy with thrombolytic agents. A stroke may be defined as a neurological deficit that has a sudden onset, lasts more than 24 hours, and results from cerebrovascular disease. A stroke occurs when there is a disruption of blood flow to a region of the brain. Blood flow is disrupted because of an obstruction of a vessel, on account of a thrombus or embolus, or the rupture of a vessel. The clinical features seen depend on the location of the event and region of the brain the vessel perfused. Approximately three-fourths of strokes are due to vascular obstruction (thrombi or emboli), resulting in ischemia and infarction. About one-fourth of strokes are hemorrhagic, resulting from hypertensive vascular disease (which causes an intracerebral hemorrhage), a ruptured aneurysm, or an arteriovenous malformation. Approximately 750,000 strokes occur every year in the US The incidence in men is greater than in women. It is estimated that there are 3 million stroke survivors and that stroke is a leading cause of disability and a leading diagnosis for long- term care. Risk factors for stroke include smoking, hypertension, obesity, cardiac disease, hypercholesterolemia, diabetes, and use of birth control pills. Prevention efforts focus on lifestyle changes that can modify risk factors. In addition, the appropriate use of warfarin or aspirin in patients at risk for cardiac sources of emboli (e.g., atrial fibrillation) constitutes primary prevention. When blood flow to any part of the brain is impeded as a result of a thrombus or embolus, oxygen deprivation of the cerebral tissue begins. Deprivation for 1 minute can lead to reversible symptoms, such as loss of consciousness. Oxygen deprivation for longer periods can produce microscopic necrosis of the neurons. The necrotic area is then said to be infarcted. If the neurons are ischemic only and have not yet necrosed, there is a chance to save them. The ischemic cascade begins within seconds to minutes after perfusion failure, creating a zone of irreversible infarction and surrounding area of potentially salvageable “ischemic penumbra.” A stroke caused by an embolus may be a result of blood clots, fragments of atheromatous plaques, lipids, or air. Emboli to the brain most often have a cardiac source, secondary to myocardial infarction or atrial fibrillation If hemorrhage is the etiology of a stroke, hypertension often is a precipitating factor. Vascular abnormalities, such as arteriovenous malformations and cerebral aneurysms, are more prone to rupture and cause hemorrhage in the presence of hypertension. The most frequent neurovascular syndrome seen in thrombotic and embolic strokes is due to involvement of the middle cerebral artery. This artery mainly supplies the lateral aspects of the cerebral hemisphere. Infarction to that area of the brain can cause contralateral motor and sensory deficits. If the infarcted hemisphere is dominant, speech problems result, and dysphasia may be present. Dysphasia: difficulty in speaking and putting words into the correct order A stroke is usually characterized by the sudden onset of focal neurological impairment. The patient may experience signs such as weakness, numbness, visual changes, dysarthria, dysphagia, or aphasia. dysarthria :difficulty in speaking words clearly, caused by damage to the central nervous system dysphagia :difficulty in Swallowing aphasia : a condition in which a person is unable to speak or write, or to understand speech or writing because of damage to the brain centres controlling speech The manifestations of a stroke depend on the anatomical location of the lesion. If symptoms resolve in less than 24 hours, the event is classified as a transient ischemic attack (TIA). Most TIAs last for only minutes to less than an hour, which further clouds recognition and prompt treatment. Furthermore, the differential diagnosis of stroke includes ruling out intracerebral hemorrhage, SAH, subdural or epidural hematoma, neoplasm, seizure, or migraine headache The time of symptom onset to administration of thrombolytic therapy (or “time to needle”) should be within a 3-hour window. patients history helps determine what has happened to the individual. It is important to obtain a description of the neurological event; how long it lasted; and whether the symptoms are resolving, completely gone, or the same as at the time of onset. Determination of risk factors for stroke, such as hypertension, chronic atrial fibrillation, elevated serum cholesterol, smoking, oral contraceptive use, or a familial history of stroke, also aids in diagnosis CT scan of the brain without contrast, is obtained within 60 minutes of arrival Blood studies (including complete blood cell count, electrolytes, glucose, and coagulation parameters, are obtained) neurological examination, and a screen performed using the National Institutes of Health Stroke Scale (NIHSS) Cerebral angiography has been the gold standard for evaluating cerebral vasculature. (ECG) should be obtained to assess for evidence of arrhythmia or cardiac ischemia Additional tests that can be done are transesophageal echocardiography (TEE) and Holter monitoring. The management of an ischemic stroke comprises four primary goals: 1. restoration of cerebral blood flow (reperfusion), 2. prevention of recurrent thrombosis, 3. neuroprotection, 4. supportive care. The focus of initial treatment should be to save as much of the ischemic area as possible. Three ingredients necessary to this area are oxygen, glucose, and adequate blood flow. The oxygen level can be monitored through (ABGs), and oxygen can be given to the patient if indicated. Hypoglycemia can be evaluated with serial checks of blood glucose. Reperfusion may be accomplished by the use of IV tissue plasminogen activator (t-PA). Cerebral perfusion pressure is a reflection of the systemic blood pressure, ICP, functioning autoregulation in the brain, and heart rate and rhythm. The parameters most easily controlled externally are the blood pressure and cardiac rate and rhythm. Arrhythmias usually can be corrected. If the patient is a candidate for thrombolytic therapy, treatment with t-PA begins in the emergency department, and he or she is then moved to the ICU for further monitoring. If the individual is not a candidate for thrombolytic therapy, the complexity of the patients problems determines his or her placement in the ICU, medical unit, or stroke specialty unit. Thrombolytic agents: IV thrombolytic therapy should be initiated within 3 hours or less of the onset of neurological symptoms. The direct administration of a thrombolytic into a vessel is an alternative to IV t-PA. Such administration is effective in acute ischemic stroke and can be given up to 6 hours after the onset of symptoms secondary treatment options for stroke include anticoagulation with antithrombotic and antiplatelet agents. If a patient experiences atrial fibrillation, anticoagulation with warfarin (Coumadin) may be necessary. Antiplatelet drugs include dipyridamole-ER, ticlopidine, clopidogrel, and aspirin. These agents discourage platelets from adhering to the wall of an injured blood vessel or other platelets and are given to prevent a future thrombotic or embolic event If the diastolic blood pressure is above approximately 105 mm Hg, it may need to be lowered gradually. This may be accomplished effectively with labetalol. The usual methods of controlling increased ICP can be instituted: hyperventilation; fluid restriction; head elevation; avoidance of neck flexion or severe head rotation that would impede venous outflow from the head; and the use of osmotic diuretics (mannitol) to decrease cerebral edema In patients with carotid stenosis, carotid endarterectomy may be performed to prevent a stroke. Assessment Plan Emotional and Behavioral Modification Communication (Expressive Dysphasia instruct in strategies of fall prevention. Establish an effective method of communication. Assess ability to speak and to follow simple commands. Arrange for consultation with speech language pathologist to differentiate language disturbances. Use communication aids such as picture cards and pantomime to enhance communication. Provide a calm, unrushed environment. Listen attentively to the patient. Speak in a normal tone. Maintain adequate airway ,oxygen ) implement calorie count if necessary. Obtain dietary consultation to obtain recommendation for supplements. Achieve urinary continence Perform assessment of usual patterns and habits. Establish a toileting schedule using a bedpan, urinal, or bedside commode. Monitor for the development of urinary retention or urinary tract infection. Use bladder scanner to evaluate contents of bladder. Avoid use of indwelling catheter to prevent infection. Establish the cause of the problem and type (bowel/bladder). Determine the clients usual voiding or bowel movement pattern. Implement an individualized bladder training program. Use an intermittent catheterization program if urinary incontinence is due to upper motor lesion. Place the client on a bedpan or commode every 2 hours. Encourage fluids to 2000 per day unless contraindicated Impaired Physical Mobility - Self-Care Deficit Perform active and passive range-of-motion exercises at least daily. Position the client in proper body alignment carefully. Maintain correct use of splints and braces. Use antiembolism stockings; Position and mobilize the client frequently as soon as possible to prevent deep-vein thrombosis or pneumonia. Measure thighs and calves daily and check for positive Homans sign (possible deep-vein thrombosis). Prevent dysrhthmias Monitor vital signs closely. Manage blood pressure carefully; avoid sharp drops in blood pressure that could result in hypotension and cause an ischemic event secondary to hypotension. During cardiac monitoring phase, identify dysrrhythmias. Treat dysrrhythmias to maintain adequate cerebral perfusion press