Monitoring the Depth of Anesthesia and Current Technology

General anesthesia (GA) is defined as a drug-induced loss of consciousness during which patients are not arousable, even by painful stimulation [1]. GA takes an important role in surgical procedures where an anesthetic overdose may lead to drug-associated toxicities, coma and even death; on the other hand a light anesthetic dose may lead to the well-known event of intraoperative awareness, which can cause sleep disorders, depression, night terrors, hospitals fears and post-traumatic stress disorder [2-4]. In this context, monitoring depth of anesthesia has become an important issue in anesthesiology.