Intra-Aortic Balloon Pump

Definition

An intra-aortic balloon pump (IABP) is a mechanical device used to temporarily decrease the workload of the heart and increase blood flow so that the heart can heal.

Purpose

An IABP is a lifesaving device used for critically ill patients with severely weakened hearts. It assists the heart in pumping by increasing blood flow to the heart muscle and by decreasing the heart's workload through a process call counterpulsation. This gives the heart muscle a chance to rest while increasing blood flow and oxygen level to the coronary arteries. The coronary arteries are the arteries that supply blood to the heart itself.

IABPs are used in patients recovering from A heart attack (myocardial infarction) or who are in cardiogenic shock. It is also used during or after open heart surgery and for critically ill patients awaiting a heart transplant. It may be used in emergency situations involving A heart attack, congestive heart failure, or failed angioplasty the heart has the possibility of recovering from these conditions. IABP cannot be used in patients with heart valve malfunction, aortic aneurysm, or in patients with irreversible cardiac damage who are not awaiting a heart transplant.

Description

An IABP is a long, flexible tube (catheter) with an inflatable balloon on one end. It is inserted through an artery in the groin (femoral artery) and threaded through blood vessels until the tip of the balloon can be placed inside the descending aortic arch. The aorta is a large, arched artery through which oxygenated blood leaves the heart. Blood flowing through the aorta goes into the coronary arteries that supply the heart muscle and to other arteries that supply the rest of the body. The balloon at the tip of the catheter is connected to a supply of gas that allows it to inflate and deflate with each heartbeat. Usually helium is the gas of choice, although occasionally carbon dioxide is used to inflate the balloon. The timing of inflation and deflation is set by a computer-controlled console.

Operation

During each contraction of the heart muscle, blood is forced out of the left ventricle and into the aorta. During each period of relaxation, blood flows into the heart chambers. When the heart relaxes (diastole), the balloon inflates. This raises blood pressure and forces more blood out into the coronary arteries, thus increasing the amount of oxygen available to the heart muscle. When the heart contracts (systole), the balloon rapidly deflates. This causes a sudden drop in blood pressure and decreases the work the heart must do to empty.

Maintenance

An IABP is a temporary device. It is normally not used for more than five days. After 24-48 hours, the patient begins being weaned off of the device. Weaning is done by having the balloon inflate and deflate only on every second or third heartbeat. Patients with IABP are cared for in the critical care unit of a hospital with a 1:1 nurse to patient ratio. Every hour the nurse takes preventive steps to keep blood clots from forming at the tip of the balloon. The patient's heart health and cardiac output are monitored continuously and a chest x ray is done every day to make sure the IABP remains located in the correct place.

Health care team roles

Placement of the IABP is done by a team that at minimum includes a radiologist, radiology technician, cardiologist, and two nurses. A critical care nurse with special training in IABP therapy monitors the patient continuously after the device is in place and remains in close communication with the cardiologist.

KEY TERMS

Aneurysm— A bulge or weak spot in an artery.

Angioplasty— A surgical procedure in which an inflatable balloon is attached to a thin tube and then threaded through a partially blocked blood vessel. When the balloon is inflated, the vessel is widened and blood flow is improved.

Cardiogenic shock— A condition that occurs when the heart is so damaged that it is not able to supply enough blood to the body.

Counterpulsation— A technique that synchronizes the external pumping of blood with the heart's cycle to assist the circulation and decreasing the work of the heart. Counterpulsation pumps when the heart is resting to increase blood flow and oxygen to the heart. Counterpulsation stops pumping when the heart is working to decrease the heart's workload and lessen oxygen demand.

Training

Critical care nurses receive special continuing education training in the use of IABP therapy.

Resources

PERIODICALS

Little, Cindy. "Your Guide to the Intra-aortic Balloon Pump." Nursing 34(December 2004): 32cc1-32cc2.

ORGANIZATIONS

American Heart Association. 7272 Greenville Avenue, Dallas, TX 75231. (800) 242-8721. 〈http://www.americanheart.org〉.

OTHER

Overwalder, P. J. "Intra Aortic Balloon Pump (IABP) Counterpulsation." The Internet Journal of Thoracic and Cardiovascular Surgery. 2(1999) 〈http://www.rjmatthewsmd.com/Definitions/IABP_counterpulsation.htm〉 (November 23, 2005).

"Principles of Intraaortic Balloon Pump Therapy." Cardiology in Critical Care—IABP. September 22, 2005. 〈http://www.rnbob.tripod.com/iabp.htm〉 (November 26, 2005).