tailieunhanh - Perioperative Critical Care Cardiology - part 9

Tăng mức độ nghiêm trọng của chấn thương phẫu thuật và gây mê có thể bắt đầu gia tăng trạng thái viêm và hypercoagulable [1]. Tình trạng viêm liên quan đến việc gia tăng yếu tố hoại tử khối u-α, interleukin-1 (IL-1), IL-6 và protein phản ứng | Prevention and Management of Cardiac Dysfunction during and after Cardiac Surgery 227 Fig. 1. Time course of ventricular function after cardiopulmonary bypass. Reproduced with permission from 5 Causes of Postoperative Myocardial Dysfunction and Failure Increasing severity of surgical trauma and anesthesia can initiate increasing inflammatory and hypercoagulable states 1 . The inflammatory state involves increases in tumor necrosis factor-a interleukin-1 IL-1 IL-6 and C-reactive protein. These factors may have a direct role in initiating plaque fissuring and acute coronary thrombosis. The hypercoagulable state involves increases in plasminogen activator inhibitor-1 factor VIII and platelet reactivity as well as decreases in antithrombin III. All these factors can lead to acute coronary thrombosis. The stress state involves increased levels of catecholamines and cortisol. Increased stress hormone levels result in increases in blood pressure heart rate coronary artery sheer stress relative insulin deficiency and free fatty acid levels. Coronary artery shear stress may trigger plaque fissuring and acute coronary thrombosis. The other factors increase oxygen demand and can result in perioperative myocardial ischemia which is strongly associated with perioperative myocardial infarction. Factors that can initiate a hypoxic state include anemia hypothermia through shivering and suppression of breathing. Cardiac surgery per se may cause additional myocardial damage by numerous mechanisms such as diffuse ischemia from inadequate myocardial 228 H. Gombotz protection and myocardial reperfusion injury inadequate repair myocardial infarction inflammation coronary spasm local trauma by surgical manipulation air embolism or residual hypothermia. Myocardial injury during cardiac surgery can be divided into three phases prebypass ischemia including preoperative disease status unprotected ischemia protected ischemia electively initiated by cardioplegia and .