Awareness During Surgery Despite Anesthesia Often Leads to Trauma: Report

While horror stories are rare involving individuals remaining awake and aware during surgery, despite use of anesthesia and paralyzing drugs that keep them from moving, a new study suggests that those who do wake up during surgical procedures are often severely traumatized by the experience.

Known as anesthesia awareness, the rare complication may occur when patients are not given proper amounts of general anethetic or analgesic to render them unconsious during the procedure. However, drugs used to prevent involuntary muscle movements during surgery leave the patient unable to communicate their awareness to the healthcare providers during the procedure.

While prior research estimated that awareness during surgery may occur in one out of every 600 patients, the findings of a new study suggest that it is far less common, likely only impacting one in every 19,000 patients. However, the risk of anesthesia awareness still poses a serious concern, given the potential long-term side effects that may be associated with the event.

In a study published by the British journal Anaesthesia on September 15, researchers found that more than half of individuals who experience anesthesia awareness are distressed by the event and many suffer psychological problems that plague them for years.

The research is the largest of its kind, examining procedures in public hospitals in five countries over a period of one year. The study was part of the 5th National Audit Project (NAP5), which has been conducted by the Royal College of Anaesthetists and the Association of Anesthetist of Great Britain and Ireland.

Data involving more than 3 million general anesthetics from public hospitals in the UK and Ireland were examined.

Rare But Traumatic Anesthesia Awareness

Formally known as “accidental awareness during general anesthesia” (AAGA), this is one of the most feared complications for anesthesiologists and patients, leaving individuals awake and experiencing the pain and discomfort of the procedure, but unable to move or speak.

In many cases of general anesthesia, the episodes are short-lived and usually occur before surgery begins or after it finishes. This does not always cause patients anxiety or concern, researchers report.

However, in 51% of cases, the episode led to patient distress. In 41% of cases, experiencing anesthesia awareness led to longer-term psychological consequences.

According to the findings of a prior study published in June 2014, patients who experience anesthesia awareness episodes do not have a risk of suffering from post-traumatic stress disorder (PTSD). Researchers found no different psychosocial outcomes among patients who were aware during surgery when compared with those given proper anesthesia. Patients who experienced an awareness episode did not develop PTSD later in life.

Muscle Relaxants Often Involved

Jaideep Pandit, lead author of this most recent research and consultant anesthesiologist in Oxford, said the effects of anesthesia awareness are closely linked with patients who experience the sensation of paralysis during the episode.

In many instances, muscle relaxants play a role, although they are often needed for safe surgery.

“The use of some emergency drugs heightens risk, as does the use of certain anaesthetic techniques,” said Pandit. “However, the most compelling risk factor is the use of muscle relaxants, which prevent the patient moving.”

“We found that patients are at higher risk of experiencing AAGA during caesarean section and cardiothoracic surgery, if they are obese or when there is difficulty managing the airway at the start of anaesthesia,” said Pandit.

Patients report a wide range of sensations during anesthesia awareness, including a tugging, stitching, pain paralysis and choking. They also described feelings of dissociation, extreme fear, suffocation and even a sensation of dying.

Researchers also said distress at the time of the experience appears to be key in development of psychological symptoms later on. Brain monitors are often used to reduce the risk of anesthesia awareness, but the study found the brain monitors provided no benefit in the situation and they do not recommend them.

Overall, researchers say the large scope of the study has offered important information and they recommended certain changes to help minimize episodes in the future. Should anesthesia awareness occur, other recommendations are being offered to help anesthesiologists recognize the situation and manage how to handle episodes to mitigate long-term effects to patients.