Artificial organs
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Severe bleeding remains the most common complication of extracorporeal membrane oxygenation (ECMO) following surgical repair of congenital heart defects. We present a case of excessive hemorrhage within the first hours on ECMO support after repair of a type I truncus arteriosus. Bleeding control was achieved by surgical repair following failure of conventional interventions to control hemorrhage despite normalization of laboratory coagulation parameters. Aspects associated with bleeding and bleeding control during extracorporeal circulation after cardiac surgery are discussed.
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The treatment of cardiogenic shock using inotropic agents and vascular volume expansion places an added burden on the heart. The resultant increase in cardiac work may cause myocardial ischemia and lead to cardiac arrest. Extracorporeal membrane oxygenation (ECMO) may be used to treat cardiogenic shock. ⋯ The rise in blood pressure associated with restoring systemic circulation afterloads the heart and can cause left atrial hypertension and pulmonary edema. ECMO does not automatically reduce cardiac work, especially in the presence of residual shunts. Left atrial drainage or decompression may be essential in certain patients both to avert pulmonary edema and to reduce cardiac work.
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The hemostatic system poses a major problem in extracorporeal membrane oxygenation (ECMO). The foreign surface in the extracorporeal circuit activates platelets and the clotting system. To avoid loss of platelets and activation of the clotting system, anticoagulation is necessary. ⋯ Most ECMO centers use heparin for anticoagulation and the activated clotting time (ACT) for monitoring. Reduction of problems with hemostasis may be obtained with less thrombogenic surfaces, new anticoagulants with a short half-life, platelet inhibitors, protease inhibitors, or selective anticoagulation in the extracorporeal circuit. While there will probably never be a complete nonthrombogenic surface available and all anticoagulants will have some risk of bleeding, improvement can be obtained by a combination of measures including better surfaces, more sophisticated anticoagulation regimens, and close laboratory monitoring.