Pericardiocentesis Health Article

Definition

A procedure performed with a needle to remove fluid for diagnostic or therapeutic purposes from the tissue covering the heart (pericardial sac).

Purpose

The heart is surrounded by a membrane covering called the pericardial sac. The sac consists of two layers, the parietal (outer) and visceral (inner) layer, and normally contains a small amount of fluid to cushion and lubricate the heart as it contracts and expands. When too much fluid gathers in the pericardial cavity, the space between the pericardium and the outer layers of the heart, a condition known as pericardial effusion occurs. Abnormal amounts of fluid may result from:

• pericarditis, infection caused by inflammation of the pericardial sac
• trauma, such as an abnormal collection of blood due to an accident
• surgery or invasive heart procedures
• heart attack (myocardial infarction) or congestive heart failure, which occurs when the heart looses its pumping capability due to a heart condition
• kidney (renal) failure
• cancer (producing malignant effusions)

The rate of pericardial fluid accumulation is important. If fluid accumulation develops slowly, then problems with blood flow will not develop until fluid retention becomes massive. Blood can also enter the pericardial sac (hemopericardium) due to trauma, blood-thinning medications, or disease. When there is rapid or excessive build-up of fluid or blood in the pericardial cavity, the resulting compression on the heart impairs the pumping action of the vascular system (a condition called cardiac tamponade). Pericardiocentesis can be used in such an emergency situation to remove the excess accumulations of blood or fluid from the pericardial sac. For diagnostic purposes, pericardiocentesis may be advised in order to obtain fluid samples from the sac for laboratory analysis.

Prior to the discovery of echocardiography, pericardiocentesis was a risky procedure. The clinician had to insert a long needle below the breastbone into the pericardial sac without internal visualization. This blind approach was associated with damage to the lungs, coronary arteries, myocardium, and liver. However, with direct visualization using echocardiography, pericardiocentesis can now be performed with minor risk. Some risk is still associated with the procedure since it is considered an invasive measure.

Demographics

Cardiac tamponade and pericarditis are two primary complications that require intervention with pericardiocentesis. Cardiac tamponade has an incidence of two in 10,000 the general U.S. population. Approximately 2% of cases are attributed to injuries that penetrate the chest. Pericarditis is more common in males than females with a ratio of seven to three. In young adults, pericarditis is usually caused by HIV infection or a trauma injury. Malignancy or renal failure are the main causes of this disorder in the elderly.

Description

The patient should sit with the head elevated 30-40 degrees. This is done to maximize fluid drainage. A site close to the pericardial sac is chosen, and if time permits the patient is sedated. The puncture site is cleaned with an antiseptic iodine solution, and the area is shaved and anesthetized with lidocaine (a local anesthetic). A long cardiac needle is inserted under the xiphoid (the bottom of the breastbone) approach on the left side of the heart using guided imagery into the chest wall until the needle reaches the pericardial sac. Usually, the patient may experience a sensation of pressure when the tip of the needle penetrates the pericardial sac. When guided imagery confirms correct placement, fluid is aspirated from the sac.

If the procedure is performed for diagnostic purposes, aspirated fluid can be collected in specimen vials and sent for pathological analysis (i.e. for cancer cell detection in cases where malignant effusion is suspected), or the fluid is just removed if the procedure was performed urgently (i.e. cardiac tamponade). For therapeutic cases, a pericardial catheter may be attached and fixed into position to allow for continuous drainage. When the needle is removed, pressure is applied for five minutes at the puncture site to stop the bleeding, and the site is bandaged.