Awareness under anesthesia occurs in around .1 to .2 percent of general anesthesia cases, or one to two documented cases in every thousand surgeries. The rarity of anesthesia awareness has declined radically, thanks to a number of developments in the field of anesthesiology, making awareness under anesthesia thankfully extremely rare. That said, it can be extremely traumatic, and patients who experience anesthesia awareness are generally encouraged to seek psychological treatment to address the emotional trauma associated with this rare surgical complication.
Anesthesia awareness, also called unintended intraoperative awareness, is a surgical complication characterized by patient awareness of a surgical procedure despite the use of a general anesthetic. There are a number of different types of anesthesia awareness. For example, some people remember the procedure, but do not have any physical sensations, while others experience pressure or pain as the surgery is performed. Some patients are actually able to interact with the surgical team under anesthesia, demonstrating the fact that the anesthesia is not working as intended, while others may be unable to communicate.
The issue of awareness under anesthesia is complicated by the use of paralytic medications in anesthesia. Patients are often given muscle relaxants to make it easier to provide care during surgery, which means that they cannot move to speak to indicate that they are experiencing pain or awareness. Anesthesia awareness often results in an increased heart rate, dilated pupils, or crying, but these symptoms are also common reflexes, making it difficult to determine if the patient is in genuine pain or panic, or if the body is simply reacting normally to surgery.
A number of causes can be responsible for awareness under anesthesia. The most common cause is the use of a light anesthetic, as is common in obstetrical cases, emergency surgery, or high-risk surgery, where deep anesthesia could kill the patient. Because each body responds differently to anesthesia, and because many different types are available, it is hard to predict how a patient will respond. Awareness under anesthesia is most common in obstetrics and trauma cases, supporting the idea that light anesthetics are commonly responsible.
Anesthesiologists use a number of techniques to reduce the risk of awareness under anesthesia. Monitors are used to keep track of brain and heart activity, and close attention is paid to reflexes which could indicate that the patient is conscious, but unable to communicate due to the anesthetic. Patients with a history of adverse reactions to anesthesia may also be treated with special care, to prevent the risk of a recurring reaction or an episode of awareness.
Because awareness under anesthesia is rare, while it is a good idea to recognize it as a potential complication of anesthetic, it should not be viewed as a reason to avoid a medical procedure which could require anesthetic. Surgeons and anesthesiologists are usually happy to discuss the issue with patients, and to address any specific concerns which people have. In the event that awareness is experienced, if the surgical team does not become aware of it during the procedure, hospital staff should be notified as soon as possible after the procedure.