Pericardiocentesis is a therapeutic and diagnostic procedure in which fluid is removed from the pericardium, the sac that surrounds the heart.
The pericardium normally contains only a few milliliters (less than a teaspoon) of fluid to cushion the heart. Many illnesses cause larger volumes of fluid, called pericardial effusions, to develop. Spread of cancer to the pericardium is a frequent cause of pericardial effusions. If an effusion is too large, pressure develops within the sac that can interfere with the normal pumping action of the heart. Should that interference become severe, a life-threatening condition called cardiac tamponade can develop, which can lead to shock or death.
Pericardiocentesis is a procedure to remove that fluid, which allows the heart to pump normally again. The fluid is analyzed for the presence of cancer cells or microorganisms. If cardiac tamponade is present, pericardiocentesis must be done on an urgent basis. If tamponade is not present, an elective surgical pericardial drainage procedure can be scheduled.
The presence of tamponade is a medical emergency and requires urgent treatment. The blood pressure can be low and breathing compromised. Fluids and intravenous medications might be needed to raise the blood pressure until the pericardiocentesis can be performed.
When possible, pericardiocentesis is performed in the cardiac catheterization laboratory of the hospital, but it can be done at the bedside or in the emergency department. The patient lies on his or her back with the head elevated at about 45 degrees. The skin is sterilized and local anesthetic given. A long needle attached to a large sterile syringe is inserted under the breastbone into the pericardium. If available, an echocardiogram or cardiac ultrasound is done to guide the physician to the pericardium. Once the needle is in the pericardium, the doctor withdraws the pericardial fluid into the syringe. The fluid can then be tested for cancer cells. If the volume of the fluid is large or likely to reaccumulate, a catheter or drain is placed with one end in the pericardial space and the other outside the chest, attached to a collecting bag. This can stay in place for several days, until there is no more fluid to drain. After withdrawing either the needle or the catheter, the doctor will apply direct pressure to the site.
If a pericardiocentesis is unsuccessful at draining the pericardial effusion, other procedures are available such as percutaneous balloon pericardiotomy, in which a balloon-tipped catheter is inserted through the skin and then used to puncture a hole in the pericardium. This is a painful procedure and should be done under anesthesia. The pericardial fluid is allowed to drain into the chest cavity, into the pleural space, the area between the pleura, the membranes that line the lungs, and the lungs themselves. The pleural space can accommodate more fluid than the pericardium without significant discomfort.
Alternatively, if emergent pericardiocentesis is unsuccessful, the patient can be taken to the operating room for a surgical procedure that will drain the fluid. These elective surgical procedures are similar to pericardiocentesis; however, for open surgical procedures, image guidance is not necessary. These are typically performed under general anesthesia. These procedures present the surgeon with the opportunity to perform a biopsy of the pericardium, to confirm the suspicion that the patient's cancer has metastasized there. The operation can also be performed as a thoracoscopic procedure.
Finally, if necessary, a pericardiectomy, sometimes called a pericardial stripping, can be performed. This is a surgical procedure to remove the pericardium and is reserved for the most refractory cases. Pericardiectomy tends to carry more risk than other procedures.
For a scheduled pericardiocentesis, a patient will take nothing by mouth for several hours before the procedure. The patient will undergo preoperative blood tests, an electrocardiogram, and an echocardiogram or ultrasound of the heart.
Most patients are admitted to an intensive care unit for monitoring after a pericardial drainage procedure. Frequent checks of blood pressure and pulse will be done, and the neck veins will be examined for bulging. Such bulging might indicate a bleeding complication. If a drain has been placed, the fluid collected will be measured, and the site checked for signs of bleeding or infection. Most patients spend several days in the hospital after pericardial drainage, but a few who do not have drains placed can go home the next day.
There is about a 5% risk of complications with a pericardiocentesis. These risks include:
- cardiac arrest
- myocardial infarction or heart attack
- abnormal heart rhythms
- laceration or puncture of the heart muscle
- laceration of the coronary arteries
- laceration of the lungs
- laceration of the stomach, colon or liver
- air embolism, in which a pocket of air becomes trapped in a blood vessel, blocking blood flow
When a pericardial effusion is caused by the presence of cancer cells, there is also a risk that the fluid might reaccumulate. Injecting irritants into the pericardial sac can initiate scarring of the pericardium. This causes it to adhere to the surface of the heart and prevents fluid from collecting there again. The irritating or sclerosing agents that are instilled into the pericardial space through a catheter include tetracycline, minocycline, and bleomycin. The injection of these drugs into the pericardium can cause pain. Sometimes, the simple presence of a drainage catheter will introduce the desired scarring, and this method is preferred, when possible, to the use of the irritant drugs.
The most important result is the relief of tamponade or other symptoms of heart failure from excess pericardial fluid. The blood pressure should return to normal, chest pain should be relieved, and breathing should become easier.
The fluid will be analyzed. Normal pericardial fluid is clear, has no cancer cells, no evidence of infection, and fewer than 1, 000 white blood cells.
On rare occasions, the pressure changes surrounding the heart that occur after pericardial drainage can cause temporary worsening of symptoms. This is called pericardial shock.
The most likely cause of a pericardial effusion in a person with cancer is spread of cancer to the pericardium. Thus, the fluid might, upon analysis, contain cancerous cells, high levels of protein, and many white blood cells. This can make the fluid thick and viscous. If the pericardial biopsy is performed, as can be done with a
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Marianne Vahey, M.D.
—The thin membrane that surrounds the heart.
—Drugs that are instilled into parts of the body to deliberately induce scarring.
—A medical emergency in which fluid or other substances between the pericardium and heart muscle compress the heart muscle and interfere with the normal pumping of blood.