Management of Acute Stroke in Critically Ill Patients

While efforts are underway to determine the mechanism of acute cerebrovascular disease, the patient should be given supportive care to maintain general medical status. Particular attention should be directed to monitoring blood pressure (BP), fluid intake, urine output, and serum and urine electrolyte levels to ensure proper fluid balance. Constant observation in a neurologic intensive care unit (NICU) with monitoring of vital signs is advised for the first few days after large or progressive cerebral infarction and most intracerebral hemorrhages (ICHs) and subarachnoid hemorrhages (SAHs). In the absence of an NICU, admission to a medical intensive care unit is recommended.

The initial physical examination should include general and neurologic (including neurovascular) examinations (see Chapters 4, 5, 6). Cardiac monitoring and observations every 4 hours with recording of vital signs (level of consciousness, BP, pulse, temperature, and respiration), pupillary size and reaction, and limb movements are recommended during at least the first few days after onset of an uncomplicated, acute, persistent cerebrovascular event, but half-hourly clinical observations and intermittent monitoring of blood gases and intracranial pressure (ICP) may be necessary for patients with severe stroke, especially those with impaired consciousness and/or fluctuating neurologic symptoms. Patients who have cerebral infarction and have received thrombolytic therapy or endovascular therapy should have frequent clinical assessment and monitoring of vital signs, including BP, particularly during the first 24 hours after treatment. In general, nursing staff should record neurologic observations and vital signs every 15 minutes for 2 hours after starting thrombolytic therapy, then every 30 minutes for 6 hours, and then hourly from the 8th hour until 24 hours after thrombolytics were started. The National Institutes of Health Stroke Scale (see Appendix C-2) is intermittently used to provide an objective assessment of the neurologic deficit. For patients in coma, the Glasgow coma scale (see Appendix B) and FOUR Score (see Chapter 6) are used to provide an objective initial and longitudinal assessment of neurologic function. Noncontrast computed tomography (CT) should be performed as an emergency procedure for all critically ill patients with probable acute cerebrovascular disorders. For patients with cerebral ischemia, a CT perfusion study provides an urgent assessment to distinguish between the infarcted core and ischemic penumbra to facilitate decision making in performing thrombolytic or mechanical thrombectomy therapy.

Immediate therapeutic measures for all comatose patients include establishing a good airway and insertion of a large-bore intravenous catheter to draw blood for studies and to maintain fluid and electrolyte balance. As noted in Chapter 6, for patients in whom the cause of coma is not readily known, naloxone, 0.4 mg intravenously, should be given with thiamine, 100 mg intravenously, followed by administration of 25 to 50 mL of 50% dextrose in water. If benzodiazepine overuse
is suspected, then flumazenil may be administered. Fluid administration should be kept to a minimum (usually 1,000 mL normal saline per m² body surface area per day), unless the patient is hypotensive or clearly dehydrated (see later).

AIRWAY MANAGEMENT

Maintenance of a patent airway is the first priority in the care of an unconscious patient or any alert patient with respiratory problems such as shallow and irregular respirations or labored breathing. The most common causes of airway obstruction are posterior displacement of oropharyngeal soft tissue structures, nasopharyngeal vomitus, and secretions. The airway should be suctioned as necessary, with the patient placed in a lateral position to prevent airway obstruction (an oropharyngeal or nasal airway may also be useful). These measures are helpful for preventing atelectasis and bronchopneumonia. Supplemental oxygen (2-4 L per minute by nasal cannula) should be provided in the presence of decreased blood oxygen levels (arterial O₂ tension < 90 mm Hg, O₂ saturation < 95%).

Endotracheal intubation or assisted respiration is rarely indicated for patients with stroke, but these procedures should be considered in circumstances of poor airway protection that are often caused by severe tongue and/or pharyngeal weakness with inability to clear secretions, insufficient oxygenation as a result of respiratory muscle fatigue, pneumonia or aspiration, or the need for markedly sedating medications because of a prolonged seizure. Endotracheal intubation and hyperventilation may also be considered for selected patients who exhibit increased ICP either alone or with other appropriate therapy for cerebral edema.

MANAGEMENT OF SYSTEMIC CARDIOVASCULAR DISORDERS

Treatment of general circulatory problems includes control of arrhythmias, restoration of cardiac output, and treatment of acute shock or hypovolemia. Hypotension is rarely a problem in stroke or transient ischemic attack, except when there is coincident myocardial infarction (MI), sepsis, or dehydration. To maintain normotension in these situations, plasma, low-molecular-weight dextran, or normal saline may also be administered. Volume expanders that contain an excessive amount of free water (such as D₅W) should be avoided, because this can worsen any evolving cerebral edema. In patients with low BP that is unresponsive to gentle volume expansion, sympathomimetic drugs (such as epinephrine) can be administered subcutaneously or intramuscularly to increase systemic BP and cerebral perfusion. In cases of MI with vascular collapse, intravenously administered vasopressors are usually advised, with titration of the rate of infusion to maintain a stable, desired BP. If clinical heart failure is present, immediate treatment with inotropic agents (such as dobutamine) is indicated.

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