Syncope

A common neurologic sign, syncope (or fainting) refers to a transient loss of consciousness associated with impaired cerebral blood supply or cerebral hypoxia. It usually occurs abruptly and lasts for seconds to minutes. An episode of syncope usually starts as a feeling of light-headedness. A patient can usually prevent an episode of syncope by lying down or sitting with his head between his knees. Typically, the patient lies motionless with his skeletal muscles relaxed but sphincter muscles controlled. However, the depth of unconsciousness varies—some patients can hear voices or see blurred outlines; others are unaware of their surroundings.

In many ways, syncope simulates death: The patient is strikingly pale with a slow, weak pulse, hypotension, and almost imperceptible breathing. If severe hypotension lasts for 20 seconds or longer, the patient may also develop convulsive, tonic-clonic movements.

Syncope may result from cardiac and cerebrovascular disorders, hypoxemia, and postural changes in the presence of autonomic dysfunction. It may also follow vigorous coughing (tussive syncope) and emotional stress, injury, shock, or pain (vasovagal syncope, or common fainting). Hysterical syncope may also follow emotional stress but isn't accompanied by other vasodepressor effects.

Action stat!

If you see a patient faint, ensure the ABCs—a patent airway, breathing, and circulation—and take his vital signs. Then place the patient in a supine position, elevate his legs, and loosen tight clothing. Be alert for tachycardia, bradycardia, or an irregular pulse. Place him on a cardiac monitor to detect arrhythmias. If an arrhythmia appears, give oxygen and insert an I.V. catheter for medication or fluid administration. Be ready to begin cardiopulmonary resuscitation, if indicated. Cardioversion, defibrillation, or insertion of a temporary pacemaker may be required.

History and physical examination

If the patient reports a fainting episode, gather information about the episode from him and his family. Did he feel weak, light-headed, nauseous, or sweaty just before he fainted? Did he get up quickly from a chair or from lying down? During the fainting episode, did he have muscle spasms or incontinence? How long was he unconscious? When he regained consciousness, was he alert or confused? Did he have a headache? Has he fainted before? If so, how often does it occur? Obtain a complete drug history.

Next, take the patient's vital signs and examine him for any injuries that may have occurred during his fall. Place him on a cardiac monitor and assess his heart rhythm for abnormalities. Assess cardiac and respiratory status. Monitor pulse oximetry. Perform a neurologic examination.

Medical causes

Aortic arch syndrome.With aortic arch syndrome, syncope, weak or abruptly absent carotid pulses, and unequal or absent radial pulses may occur. Early signs and symptoms include night sweats, pallor, nausea, anorexia, weight loss, arthralgia, and Raynaud's phenomenon. He may also develop hypotension in the arms; neck, shoulder, and chest pain; paresthesia; intermittent claudication; bruits; vision disturbances; and dizziness.

Aortic stenosis.A cardinal late sign of aortic stenosis, syncope is accompanied by exertional dyspnea and angina. Related findings include marked fatigue, orthopnea, paroxysmal nocturnal dyspnea, palpitations, and diminished carotid pulses. Typically, auscultation reveals atrial and ventricular gallops as well as a harsh, crescendo-decrescendo systolic ejection murmur that's loudest at the right sternal border of the second intercostal space.

Cardiac arrhythmias.Any arrhythmia that decreases cardiac output and impairs cerebral circulation may cause syncope. Other effects—such as palpitations, pallor, confusion, diaphoresis, dyspnea, and hypotension—usually develop first. However, with Adams-Stokes syndrome, syncope may occur without warning. During syncope, the patient develops asystole, which may precipitate spasm and myoclonic jerks if prolonged. He also displays an ashen pallor that progresses to cyanosis, incontinence, a bilateral Babinski's reflex, and fixed pupils.

Hypoxemia.Regardless of its cause, severe hypoxemia may produce syncope. Common related effects include confusion, tachycardia, restlessness, and incoordination.

Orthostatic hypotension.Syncope occurs when the patient rises quickly from a recumbent position. Look for a drop of 10 to 20 mm Hg or more in systolic or diastolic blood pressure as well as tachycardia, pallor, dizziness, blurred vision, nausea, and diaphoresis.

Transient ischemic attack (TIA).Marked by transient neurologic deficits, TIAs may produce syncope and decreased level of consciousness. Other findings vary with the affected artery, but may include vision loss, nystagmus, aphasia, dysarthria, unilateral numbness, hemiparesis or hemiplegia, tinnitus, facial weakness, dysphagia, and a staggering or an uncoordinated gait.

Other causes

Drugs.Quinidine may cause syncope—and possibly sudden death—associated with ventricular fibrillation. Prazosin may cause severe orthostatic hypotension and syncope, usually after the first dose. Occasionally, griseofulvin, levodopa, and indomethacin can produce syncope.

Nursing considerations

▪ Monitor the patient's vital signs closely.

▪ Prepare him for an electrocardiogram and Holter monitor, carotid duplex, carotid Doppler, and electrophysiology studies.

▪ Take measures to provide for patient safety.

Patient teaching

▪ Explain the underlying disorder and treatment plan.

▪ Encourage the patient to pace his activities.

▪ Teach the patient measures to take if he feels faint.

▪ Tell the patient to rise slowly from a lying or sitting to a standing position.

Book Source Details

• Book Title: Nursing: Interpreting Signs and Symptoms
• Author(s): Springhouse
• Year of Publication: 2007
• Copyright Details: Nursing: Interpreting Signs and Symptoms, Copyright © 2007 Lippincott Williams & Wilkins.

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Copyright Details: Nursing: Interpreting Signs and Symptoms, Copyright © 2008 Williams & Wilkins.

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More About This Book: Title: Nursing: Interpreting Signs and Symptoms Authors: Springhouse Publisher: Lippincott Williams & Wilkins Copyright: 2007 ISBN: 1-58255-668-7

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