3．体外循環と人工心肺回路

Cardiopulmonary Bypass System and Perfusion

心臓血管外科手術をサポートする人工心肺は，体外循環によって循環とガス交換を維持するだけでなく，無血視野の確保，心内血や出血の回収，代謝の抑制，血液希釈と濃縮，そして心筋保護まで担う．よって，人工心肺はさまざまな構成要素で成り立っており，リスクも孕んでいる．本稿では，人工心肺の構成要素と安全装置，そして体外循環回路を中心に解説する．

In addition to maintaining circulation and gas exchange, the heart-lung machine is responsible for ensuring a bloodless field, retrieve of blood, suppression of metabolism, blood dilution and concentration, and myocardial protection. The heart-lung machine has 2 kinds of circuits having different characteristics, that is an open circuit and a closed circuit. Either a roller pump or a centrifugal pump is used in the machine. Gas exchange is performed by using a membrane type oxygenator. Venting, suction, myocardial protection circuit are important items in the machine.

Safety devices and troubleshooting are required for safety management of the heart-lung machine.