Central nervous system care in postoperative adult cardiac surgery

Abstract

CNS dysfunction after cardiac surgery is considered among the most important etiologies for morbidities and mortalities after cardiac surgery and patients undergoing cardiac surgery might be affected by unwanted CNS complications; this is a well-established finding in many studies. Although postoperative period-related factors constitute only about one-fifth (20%) of etiologies of postoperative CNS complications of cardiac surgery, the CNS complications are not usually seen intraoperatively; those CNS complications seen first during the hospitalization period are usually encountered in ICU. Two main classifications are used for categorizing postoperative CNS injuries in cardiac surgery patients. The first is mainly a clinical classification (including type I and type II disorders), while the second is a time-based classification (including early and late diseases). Advanced age, high preoperative creatinine level, prior neurological event, prolonged cardiopulmonary bypass time, and female gender are considered as early risk factors, while prior neurologic event, diabetes mellitus, unstable angina, previous cerebral vascular disease, need for inotropic support, and postoperative atrial fibrillation are considered as delayed risk factors. Aortic atherosclerosis is considered as both an acute and a chronic risk factor. The underlying mechanisms are classified into five main classes: patient-related etiologies, intraoperative surgical etiologies, intraoperative anesthetic etiologies, intraoperative extracorporeal circulation (ECC) etiologies, and postoperative period-related etiologies; a number of potential etiologies have been proposed in each class. Prevention strategies include pharmacologic neuroprotection and CPB-related techniques. Novel and older technologies are used to improve the CNS outcome.