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The Intra-aortic balloon pump (IABP) is a mechanical device that increases myocardial oxygen perfusion while at the same time increasing cardiac output. Increasing cardiac output increases coronary blood flow and therefore myocardial oxygen delivery. It consists of a cylindrical polyethylene balloon that sits in the aorta, approximately from the left subclavian artery〔(【引用サイトリンク】url=http://www.texasheart.org/Research/Devices/iabp.cfm )〕 and counterpulsates. That is, it actively deflates in systole, increasing forward blood flow by reducing afterload through a vacuum effect. It actively inflates in diastole, increasing blood flow to the coronary arteries via retrograde flow. These actions combine to decrease myocardial oxygen demand and increase myocardial oxygen supply.〔(Intensive Care Medicine ) by Irwin and Rippe〕〔(Intra Aortic Balloon Pump (IABP) Counterpulsation )(mirror with better quality ) by P. 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.〕〔(Intra-aortic balloon pumping ) Department of Anaesthesia and Intensive Care of The Chinese University of Hong Kong〕 A computer-controlled mechanism inflates the balloon with helium from a cylinder during diastole, usually linked to either an electrocardiogram (ECG) or a pressure transducer at the distal tip of the catheter; some IABPs, such as the Datascope System 98XT, allow asynchronous counterpulsation at a set rate, though this setting is rarely used. Helium is used because its low viscosity allows it to travel quickly through the long connecting tubes, and has a lower risk than air of causing an embolism should the balloon rupture. ==Indications== The following situations may benefit from this device.〔〔〔 *Cardiogenic shock when used alone as treatment for myocardial infarction. 9-22% survive the first year. *Reversible intracardial mechanical defects complicating infarction, i.e. acute mitral regurgitation and septal perforation. *Unstable angina pectoris benefits from counterpulsation. *Post cardiothoracic surgery—most common and useful is counterpulsation in weaning patients from cardiopulmonary bypass after continued perioperative injury to myocardial tissue. *Preoperative use is suggested for high-risk patients such as those with unstable angina with stenosis greater than 70% of main coronary artery, in ventricular dysfunction with an ejection fraction less than 35%. *Percutaneous coronary angioplasty *In high risk coronary artery bypass graft surgery where cardiopulmonary bypass time was shortened, as well as during intubation period and hospital stay.〔(Usage of Intra-Aortic Balloon Pump in High Risk Coronary Artery Bypass Graft Surgery by K. Jai Shankar )〕 *Thrombolytic therapy of acute myocardial infarction.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Intra-aortic balloon pump」の詳細全文を読む スポンサード リンク
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