Transcript
Chapter 17: Acute Stroke Injury
Chapter Summary
Stroke, or acute brain attack, is an acute neurologic deficit that occurs when impaired blood flow to a localized area of the brain results in injury to brain tissue. There are two major classifications of stroke: ischemic and hemorrhagic.
Ischemic strokes are caused by an interruption of cerebral blood flow that results in a TIA, thrombotic stroke, or embolic stroke. Hemorrhagic strokes occur when a cerebral blood vessel ruptures and blood accumulates in or around brain tissue. Hypertension is a common cause of intracranial hemorrhage. Hemorrhagic strokes occur with subarachnoid hemorrhage or intracerebral hemorrhage.
The majority of strokes result from ischemia caused by atherosclerotic lesions in cerebral blood vessels, resulting in diminished blood flow and decreased tissue perfusion, which causes neuronal dysfunction and cell death.
There are two zones of affected neurons in the evolution of a stroke. The central zone is composed of infarcted neurons that do not regain function. The adjacent zone is the penumbra. Cells in this zone are impaired, but still function and are capable of recovery.
The goal of medical treatment is to limit the size of the central zone and reestablish perfusion to the neurons in the penumbra.
Prevention of stroke begins with identification of modifiable and nonmodifiable risk factors. Modifiable risk factors include hypertension, hypotension, and dehydration in the elderly, coronary heart disease, dyslipidemia, hypercholesterolemia, and smoking. Elimination of these risk factors reduces the risk of stroke. Nonmodifiable risk factors include advancing age, male gender, African- American race, and family history of stroke. Nonmodifiable risk factors cannot be eliminated. Individuals with these risk factors must diligently eliminate modifiable risk factors in efforts to decrease the risk of stroke.
Manifestations of stroke vary according to the cerebral artery involved. It is important to quickly determine whether the stroke is ischemic or hemorrhagic. This determination is based on a focused neurologic assessment and diagnostic tests.
A focused clinical assessment of the patient with acute stroke is critical in order to provide the appropriate care and interventions. The assessment begins with the ABCs to identify actual or potential life-threatening problems. Key physical assessment findings may include neuromuscular abnormalities as well as cognitive, perceptual–visual–spatial defects.
Most strokes are caused by an occlusion of a cerebral vessel. Improvement and restoration of perfusion to the ischemic area are imperative. Intravenous tPA is recommended for treatment of ischemic stroke. Administration of other anticoagulant medications such as IV heparin is controversial.
Invasive procedures using cerebral angiography may be used to reverse neurological deficits caused by atherosclerotic lesions. This procedure, like all others, is associated with risks and requires frequent nursing assessments of the patient after the procedure.
Management of cerebellar lesions or subarachnoid hemorrhage requires prompt surgical intervention. Triple H therapy is used to prevent and control cerebral vasospasm postoperatively for patients who have had an aneurysm clipping.
A carotid endarterectomy is performed to remove occlusive atherosclerotic plaque in the carotid arteries. Postoperative nursing assessments focus on early identification of complications and prevention of pressure/tension on the operative site.
To increase independence, rehabilitation must begin as early as possible following stroke, and requires a multidisciplinary effort. Undernutrition of the patient is an important concern. Dysphagia, diminished or absent gag reflexes, facial paralysis, hemiplegia, an inability to perform bilateral hand tasks, and immobility all contribute to undernutrition.
Alteration in elimination may be related to impaired mobility, cognitive impairment, aphasia, and pre-existing elimination problems. Neurogenic bladder may be present and require astute nursing care. Constipation is common. Impaired sensation and skin integrity related to loss of touch, pressure, temperature, and sensation, and motor or vascular tone loss are all potential problems. Nursing interventions must address patient safety.
The patient with a stroke may experience a variety of visual–spatial–perceptual deficits. The nurse in the high-acuity setting recognizes these deficits and plans nursing care accordingly.
Nursing care of the patient with a stroke during the acute phase of recovery is extremely challenging. Impaired physical mobility is related to motor and sensory deficits, particularly hemiplegia and impaired balance, changes in postural tone, and disinhibition of primitive reflex activity.
Patients and their families are faced with multiple psychosocial stressors, which increase the risk for ineffective coping. These stressors are related to the abrupt change in lifestyle, loss of roles, dependency, and issues of economic insecurity. Significant others find themselves having to assume new roles as care providers along with having to relinquish jobs and salaries.
For the patient and family, multidisciplinary referrals may be necessary. Social workers, home health nurses, dieticians, occupational therapists, physical therapists, support groups, and voluntary and governmental agencies (e.g., Medicare) provide assistance.
