cardiac tamponade

Cardiac Tamponade 

Definition

Cardiac tamponade occurs when the heart is squeezed by fluid that collects inside the sac that surrounds it.

Description

The heart is surrounded by a sac called the pericardium. When this sac becomes filled with fluid, the liquid presses on the heart, preventing the lower chambers of the heart from properly filling with blood.

Because the lower chambers (the ventricles) cannot fill with the correct amount of blood, less than normal amounts of blood reach the lungs and the rest of the body. This condition is very serious and can be fatal if not treated.

Causes and symptoms

Fluid can collect inside the pericardium and compress the heart when the kidneys do not properly remove waste from the blood, when the pericardium swells from unknown causes, from infection, or when the pericardium is damaged by cancer. Blunt or penetrating injury from trauma to the chest or heart can also result in cardiac tamponade when large amounts of blood fill the pericardium. Tamponade can also occur during heart surgery.

When the heart is compressed by the surrounding fluid, three conditions occur: a reduced amount of blood is pumped to the body by the heart, the lower chambers of the ventricles are filled with a less than normal amount of blood, and higher than normal blood pressures occur inside the heart, caused by the pressure of the fluid pushing in on the heart from the outside.

When tamponade occurs because of trauma, the sound of the heart beats can become faint, and the blood pressure in the arteries decreases, while the blood pressure in the veins increases.

In cases of tamponade caused by more slowly developing diseases, shortness of breath, a feeling of tightness in the chest, increased blood pressure in the large veins in the neck (the jugular veins), weight gain, and fluid retention by the body can occur.

Diagnosis

When cardiac tamponade is suspected, accurate diagnosis can be life-saving. The most accurate way to identify this condition is by using a test called an echocardiogram. This test uses sound waves to create an image of the heart and its surrounding sac, making it easy to visualize any fluid that has collected inside the sac.

Treatment

If the abnormal fluid buildup in the pericardial sac is caused by cancer or kidney disease, drugs used to treat these conditions can help lessen the amount of fluid collecting inside the sac. Drugs that help maintain normal blood pressure throughout the body can also help this condition; however, these drugs are only a temporary treatment. The fluid within the pericardium must be drained out to reduce the pressure on the heart and restore proper heart pumping.

The fluid inside the pericardium is drained by inserting a needle through the chest and into the sac itself. This allows the fluid to flow out of the sac, relieving the abnormal pressure on the heart. This procedure is called pericardiocentesis. In severe cases, a tube (catheter) can be inserted into the sac or a section of the sac can be surgically cut away to allow for more drainage.

Prognosis

This condition is life-threatening. However, drug treatments can be helpful, and surgical treatments can successfully drain the trapped fluid, though it may reaccumulate. Some risk of death exists with surgical drainage of the accumulated fluid.

Resources

Organizations

American Heart Association. 7320 Greenville Ave. Dallas, TX 75231. (214) 373-6300. http://www.americanheart.org.

Key terms

Pericardiocentesis — A procedure used to drain fluid out of the sac surrounding the heart. This is done by inserting a needle through the chest and into the sac.

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tamponade /tam·pon·ade/ (tam″po-nād´)

1. surgical use of a tampon.

2. pathologic compression of a part.

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balloon tamponade  esophagogastric tamponade by means of a device with a triple-lumen tube and two inflatable balloons, the third lumen providing for aspiration of blood clots.

cardiac tamponade  compression of the heart caused by increased intrapericardial pressure due to collection of blood or fluid in the pericardium.

esophagogastric tamponade  the exertion of direct pressure against bleeding esophageal varices by insertion of a tube with a balloon in the esophagus and one in the stomach and inflating them.

Esophagogastric tamponade, using Sengstaken-Blakemore tube.

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cardiac tamponade

n.

Compression of venous return to the heart because of increased volume of fluid in the pericardium.

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cardiac tamponade

[tam′pənäd′]

compression of the heart produced by the accumulation of blood or other fluid in the pericardial sac. Also called cardiac compression, pericardial tamponade.

observations Signs of cardiac tamponade may include distended neck veins, hypotension, decreased heart sounds, tachypnea, peripheral pulses that are weak or absent or that fall sharply during inspiration (pulsus paradoxus), reduced left atrial pressure, and pericardial friction rub. The patient, who is usually anxious and restless, may sit upright or lean forward, and the skin may be pale, dusky, or cyanotic. The electrocardiogram generally shows decreased cardiac voltage and may show electrical alternans, and the chest x-ray film may reveal an enlarged heart shadow ("water bottle" heart).

interventions The patient is maintained on bed rest; the head of the bed is elevated 45 degrees, and a defibrillator and emergency drugs are kept at the bedside. IV saline is the initial therapy of choice to maintain filling pressures in the heart. Blood pressure, respiration, apical pulse, and atrial and pulmonary wedge pressures are checked every 15 to 30 minutes. Auscultation for pulsus paradoxus is performed, and peripheral pulses are checked every 30 minutes. A 12-lead electrocardiogram is usually ordered, and the patient is placed on a cardiac monitor with the rhythm strip checked every hour. A Doppler echocardiogram is done initially and may be repeated a few days later. Cardiotonic and antiarrhythmic drugs are administered as ordered. Aspiration of the fluid in the pericardial sac (pericardiocentesis) is performed, and, if surgery is indicated, the patient is prepared for the procedure. In cases in which bleeding vessels are the cause of the tamponade, the vessels are ligated.

Cardiac tamponade

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cardiac tamponade (kärˑ·dē·ak tamˈ·p·nādˑ),

n a condition caused by accumulation of fluid between the heart and the pericardium, thus resulting in excess pressure on the heart. This impairs the heart's ability to pump sufficient blood.

Cardiac tamponade.

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tamponade

1. surgical use of a tampon.

2. pathological compression of a part.

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cardiac tamponade

compression of the heart due to collection of fluid or blood in the pericardial sac. Causes interference with heart action and subsequent sudden death or congestive heart failure. The heart shadow on radiography is enlarged, the heart sounds on auscultation are muffled.

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cardiac tamponade

Interference with the venous return of blood to the heart 2º to accumulation of fluids or blood in pericardium, resulting in ↑ mean right atrial pressure and near-equalization with intrapericardiac pressure, which has a wide range of clinical and hemodynamic effects Etiology 2º to dissecting aneurysm, HTN, post-MI, renal failure, pericarditis, hypothyroidism, autoimmune disease–eg, SLE, chest trauma, CA Diagnosis Echocardiogram Management Pericardiocentesis, ie needle aspiration, pericardial window