A procedure performed with a needle to remove fluid for diagnostic or therapeutic purposes from the tissue covering the heart (pericardial sac).
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.
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.
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.
The typical symptom associated with patients requiring pericardiocentesis is chest pain, usually indicative of severe effusion. Patients with cardiac tamponade commonly have dyspnea (difficulty breathing) and those with an infection may have fever. Some patients may have a hoarse voice from compression of a nerve called the recurrent laryngeal nerve; the pericardial sac may be so large that it pushes or compresses neighboring anatomical structures. Physical symptoms may vary, dependent both on size and the rate of filling of the pericardial effusion. Patients can also present with the following physical symptoms:
- tachycardia, an increased heart rate
- tachypnea, an increase in breathing rate
- jugular vein enlargement
- narrow pulse pressure (pulsus paradoxus)
- pericardial friction rub
- elevated central venous pressure
- hiccups from esophageal compression
- Ewart's sign (dull sound when the doctor taps the chest, tactile fremitus, egobronchophony)
The procedure can be performed in an emergency room, ICU, or at the bedside. Before the procedure patients should have an echocardiogram and basic blood analysis. No special dietary restrictions are required for pericardiocentesis. The patient will receive an IV line for sedation or other necessary medications and an electrocardiogram (ECG) to monitor cardiac activity. The patient must lie flat on the table, with the body elevated to a 60-degree angle. If the test is elective, then food and water restriction is recommended for six hours before the test. For infants and children, preparation depends on the child's age, level of trust, and previous exposure to this or similar procedures.
The puncture site, or if a catheter is fixed in place, the catheter site, should be inspected regularly for signs of infection such as redness or swelling. Vital signs such as blood pressure and pulse are monitored following the procedure.
Pericardiocentesis is an invasive procedure and therefore has associated risks. Complications are possible, but have become less common due to guided imaging techniques that improved the past blind approach. Possible risks include:
- puncture of the myocardium, the outer muscle layer of the heart
- puncture of a coronary artery, a blood vessel that supplies blood to heart muscle
- myocardial infarction (heart attack)
- needle induced arrhythmias (irregular heartbeats)
- pneumopericardium, air entry into the pericardial sac
- infection of the pericardial membranes (pericarditis)
- accidental puncture of the stomach, lung, or liver
Normal pericardial fluid is clear to straw colored. During pathological examination normal pericardial fluid does not contain blood, cancer cells, or bacteria. In most individuals, a small amount of fluid (10–50 ml) is in the pericardial sac to cushion the heart. Pericardial fluid volumes over 50 ml suggest pericardial effusion. The presence of microorganisms (such as Staphylococcus aureus ) in aspirated pericardial fluid indicates bacterial pericarditis. Blood in pericardial fluid can be seen in patients with cancer; cardiac rupture, which can occur with myocardial infarction; or hemorrhage due to traumatic injury or accident.
Morbidity and mortality rates
The success of pericardiocentesis has greatly improved with the use of guided imagery during the procedure. Only about 5% of patients will experience a major complication as a result of pericardiocentesis. Cardiac tamponade is fatal in almost all cases unless the excess fluid in the pulmonary sac is removed.
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A.D.A.M., Inc. "Pericardiocentesis." January 31, 2003 [cited June 26, 2003]. University of Pennsylvania Health System. http://www.pennhealth.com/ency/article/003872.htm .
Laith Farid Gulli,, MD, MS Alfredo Mori,, MBBS Abraham F. Ettaher,, MD Robert Ramirez,, BS
WHO PERFORMS THE PROCEDURE AND WHERE IS IT PERFORMED?
A cardiologist who has received three years of training in internal medicine and three years of cardiology training typically performs the procedure. A general surgeon can also perform pericardiocentesis and typically have five years of surgical training. The procedure is performed in a hospital, either in the ER (emergency room), ICU ( intensive care unit ), or bedside.
QUESTIONS TO ASK THE DOCTOR
- Where will the procedure take place?
- What type of anesthetic will be used?
- Will this procedure be used for diagnostic purposes?
- Who will be performing the procedure?