The Intra-aortic balloon pump (IABP) is a mechanical device that is used to decrease myocardial oxygen demand while at the same time increasing cardiac output. Cardiac output (Q is the volume of blood being pumped by the Heart, in particular by a ventricle in a minute By increasing cardiac output it also increases coronary blood flow and therefore myocardial oxygen delivery. It consists of a cylindrical balloon that sits in the aorta and counterpulsates. That is, it actively deflates in systole increasing forward blood flow by reducing afterload thus, and actively inflates in diastole increasing blood flow to the coronary arteries. In cardiac Physiology, afterload is used to mean the tension produced by a chamber of the Heart in order to contract. Diastole is the period of time when the heart fills with blood after systole (contraction Coronary circulation is the circulation of blood in the Blood vessels that supply Blood to and from the Heart muscle These actions have the combined result of decreasing myocardial oxygen demand and increasing myocardial oxygen supply. [1] [2] [3] The balloon is inflated during diastole by a computer controlled mechanism, usually linked to either an ECG or a pressure transducer at the distal tip of the catheter; some IABPs, such as the Datascope System 98XT, allow for asynchronous counterpulsation at a set rate, though this setting is rarely used. The computer controls the flow of helium from a cylinder into and out of the balloon. Helium is used because its low viscosity allows it to travel quickly through the long connecting tubes, and has a lower risk of causing a harmful embolism should the balloon rupture while in use.
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History
The IABP device was pioneered at the Cleveland Clinic during the early 1960s by Moulopoulus et al. The Cleveland Clinic (formally known as the Cleveland Clinic Foundation) is a multispecialty academic medical center located in Cleveland, Ohio, [2]
Use of counterpulsation
Intraaortic balloon counterpulsation is used in situations when the heart's own cardiac output is insufficient to meet the oxygenation demands of the body. These situations could include cardiogenic shock, severe septic shock, post cardiac surgery and numerous other situations.
Indications
The following situations may benefit from this device. [1] [2] [3]
- Cardiogenic shock when used alone as treatment for myocardial infarction 9-22% survive the first year. Cardiogenic shock is based upon an inadequate circulation of Blood due to primary failure of the ventricles of the Heart to function effectively Myocardial infarction ( MI or AMI for acute myocardial infarction) also known as a heart attack, occurs when the blood supply
- Reversible intracardial mechanical defects complicating infarction, i. The heart is a muscular organ in all Vertebrates responsible for pumping Blood through the Blood vessels by repeated rhythmic e. acute mitral regurgitation and septal perforation.
- Unstable angina pectoris benefits from counterpulsation. Angina pectoris, commonly known as angina, is severe Chest pain due to Ischemia (a lack of blood and hence Oxygen supply of the heart
- Post cardiothoracic surgery most common and useful is the use of counterpulsation in weaning patients from cardiopulmonary bypass after continued perioperative injury to myocardial tissue. Cardiothoracic surgery is the field of Medicine involved in surgical treatment of Diseases affecting organs inside the Thorax (the chest
- Preoperative use has been suggested for high-risk patients such as those with unstable angina with stenosis greater than 70% of main coronary artery, in ventricaular dysfunction with an ejection fraction less than 35%. In cardiovascular physiology, ejection fraction ( Ef) is the fraction of Blood pumped out of a ventricle with each heart beat
- Bridge to heart transplant for those patients with left ventricular failure. Heart transplantation or cardiac transplantation, is a surgical transplant procedure performed on patients with end-stage Heart failure or severe Coronary
- Percutaneous coronary angioplasty
Contraindications
Absolute contraindication
The following conditions will always exclude patients for treatment:[1] [2] [3]
- Aortic valve insufficiency
- Aortic dissection
- Severe aortoiliac occlusive disease
Relative contraindication
The following conditions could, under very pressing circumstances, be allowed to be included for therapy:[1]
- Prosthetic vascular grafts in the aorta
- Aortic aneurysm
- Aortofemoral grafts
Complications
Since the device is placed in the femoral artery and aorta it could provoke ischemia, and compartment syndrome. An aneurysm (or aneurism) is a localized blood-filled dilation (balloon-like bulge of a blood vessel caused by disease or weakening of the vessel wall The femoral artery is a large Artery in the muscles of the Thigh. In Medicine, ischemia ( Greek ισχαιμία, isch- is restriction hema or haema is Blood) is a restriction Compartment syndrome is an acute medical problem following injury surgery or in most cases repetitive and extensive muscle use in which increased pressure (usually caused by inflammation At highest risk is the leg which is supplied by the femoral artery may become ischemic, but also placing the balloon too distal from the arcus aortae may induce occlusion of the renal artery and subsequent renal failure. The renal arteries normally arise off the side of the Abdominal aorta, immediately below the Superior mesenteric artery, and supply the Kidneys with Renal failure or kidney Other possible complications are cerebral embolism during insertion, infection, dissection of the aorta or iliac artery, perforation of the artery and hemorrhage in the mediastinum. Dissection (also called anatomization) is usually the process of disassembling and observing something to determine its internal structure and as an aid to discerning the function The mediastinum is a non-delineated group of structures in the Thorax (chest surrounded by Loose connective tissue. Mechanical failure of the balloon itself is also a risk which entails vascular surgery to remove under that circumstance. After balloon removal there is also a risk of 'embolic shower' from micro clots that have formed on the surface of the balloon, and can lead to peripheral thrombosis, myocardial ischemia, hemodynamic decompensation, and late pseudoaneurysm. [1] [2] [3]
Trivia
The IABP's developers thought that private insurance companies would not stand for such a radical new therapy, and approached the military, asking them to keep an eye out for IABP candidates in military hospitals. One day, the call came. A retired general was hospitalized in Walter Reed Army Medical Center. He had a history of multiple infarcts and was now end-stage heart failure. The IABP scientists were all ready to go, until they found out the general was former President Dwight D. Eisenhower. Dwight David "Ike" Eisenhower (October 14 1890 – March 28 1969 was President of the United States from 1953 until 1961 and a five-star general They declined the opportunity because they worried that if the IABP failed in him, it would permanently ruin the future prospects of the device.
See also
References
- ^ a b c d e Intensive Care Medicine by Irwin and Rippe
- ^ a b c d e Intra Aortic Balloon Pump (IABP) Counterpulsation mirror with better quality by P. Cardiogenic shock is based upon an inadequate circulation of Blood due to primary failure of the ventricles of the Heart to function effectively A Ventricular assist device, or VAD, is a mechanical device that is used to partially or completely replace the function of a failing Heart. J Overwalder, M. D. , Department of Surgery, Division of Cardiac Surgery, University Hospital Graz, The Internet Journal of Thoracic and Cardiovascular Surgery. 1999. Volume 2 Number 2.
- ^ a b c d Intra-aortic balloon pumping Department of Anaesthesia and Intensive Care of The Chinese University of Hong Kong
External links
- Intra-aortic Balloon Pump (IABP) Texas Heart Institute
- Intra Aortic Balloon Pump (IABP) two videos demonstrating inflating and deflating the balloon
- Images in cardiovascular medicine The missing intra-aortic balloon pump catheter by Pasquale Totaro, Nello Degno, John Smith, Vincenzo Argano, Cardiac Surgery Department, Regional Cardiac Center, Morriston Hospital, Swansea, UK, Ital Heart J 2005; 6 (4): 361-362)