The physiological effects of thoracic epidural anesthesia and analgesia on the cardiovascular, respiratory and gastrointestinal systems.

Studies of regional anesthesia are increasing in popularity not only for the purpose of technical advancement, but also to better understand the effects of neural deafferentation on the function of various organs. Thoracic epidural anesthesia (TEA) is one of the most versatile and widely utilized neural deafferentation techniques. The aim of this article is to critically review published data regarding the most relevant effects of TEA on the cardiovascular, respiratory and gastrointestinal systems. In the cardiovascular system, TEA modifies the electrical activity of the heart in addition to ventricular function and wall motion. Improvements in regional blood flow and a reduction of the major determinants of cardiac oxygen consumption lead to less severity of the ischemic injury. Although TEA negatively affects the performance of intercostal muscles, it spares diaphragmatic function and, when it is limited to the first five thoracic segments, affects pulmonary volumes to a lesser extent. TEA can be safely used in patients with compromised respiration. Splanchnic sympathetic block is achieved when thoracic fibers from T5 to T12 are affected in a dose-dependent manner. Improved gastrointestinal blood flow and motility are clear in animals, and in clinical studies, TEA has been shown to improve recovery after major abdominal surgery. TEA thus presents a powerful tool available to anesthesiologists for perioperative intervention, but its use alone cannot prevent postoperative morbidity and mortality. It is therefore necessary to address its use in the context of multimodal intervention.