Anesthesia awareness
Intraoperative alertness (English Awareness) is when a patient during general anesthesia (narcosis) partially or fully perceives his environment or solicitation actively followed. It can be distinguished in hindsight intraoperative states of wakefulness without remembrance of those with unconscious (implicit ) and conscious (explicit ) memory, with most affected belong to the first group.
If there are no special risks are present, occur wax phenomena with a frequency of one to two cases per 1,000 anesthetics on (0.1 to 0.2%). In children, the risk for such an event, however, at the 8 - to 10 -fold increased. A recent study from the UK, however, comes at a frequency of only 1:15,000. An increased risk for emergency surgery, caesarean section, cardiac surgery, surgery of the night, critically ill patients with impaired cardiovascular reserve ( ASA status IV, V), drug addiction, chronic pain patients, previously previous history of episodes of intraoperative awareness, the use of muscle relaxants in total intravenous anesthesia and lack of premedication with a benzodiazepine.
The experience of awareness is highly variable and may include hearing and visual awareness and the perception of pain, paralysis, helplessness and anxiety. Convalescence after surgery can significantly be impaired ( acute stress reaction), usually an experience of intraoperative awareness is not associated with long- term consequences. In some cases, it may lead to the formation of a subject in need of post-traumatic stress disorder. This can also be caused by arousal states without conscious recollection.
Measures for the prevention of awareness include the identification of risk factors prior to surgery, a standardized test of equipment, clinical monitoring of the patient (heart rate, blood pressure, pupil size, sweating, movements of the patient) and the use of depth of anesthesia monitors based on the derivation an electroencephalogram (EEG ) based. The use of these devices is controversial because there are no convincing data that the frequency of awareness can be significantly reduced. The American Society of Anesthesiologists is not recommended for this reason, the rule-based applications.