The fear of waking up while you’re being operated upon is almost up there with the fear of being buried alive. But while the latter never happens any more, if it ever did, the former is more common than you might think. A newly published review reveals that accidental awareness during general anaesthesia (AAGA) may occur in one in every 800 interventions, depending on how you define the term. And some level of responsiveness during surgery could happen in as many as one in 25 cases.
Waking up during surgery is often, understandably, a traumatic experience. Take the case of Sandra, who as a 12-year-old suffered an episode of AAGA during a routine orthodontic operation.
“Suddenly, I knew something had gone wrong,” Sandra wrote in the foreword to NAP5, a recent UK report on AAGA. “I could hear voices around me, and I realised with horror that I had woken up in the middle of the operation, but couldn’t move a muscle… while they fiddled, I frantically tried to decide whether I was about to die.”
Like many other victims of AAGA, Sandra suffered from PTSD-like symptoms for years after the event. She described nightmares in which “a Dr Who-style monster leapt on me and paralysed me.” The nightmares continued for more than 15 years before she realised the link: “I suddenly made the connection with feeling paralysed during the operation; after that I was freed of the nightmare and finally liberated from the more stressful aspects of the event.”
The account underlines a key factor in AAGA, which is the use of neuromuscular blocking agents as part of the anaesthetic mix. They paralyse the muscles, which means that if a patient wakes up for any reason, he or she cannot signal to the surgeon that anything is wrong. It can render AAGA a truly terrifying experience, during which patients can hear voices and equipment, and vainly try to move to alert staff as a feeling of dread and powerlessness sweeps over them.
The NAP5 report found that anaesthesia awareness was most common in obstetrics, and specifically in caesarian interventions. This could be because caesarians often require rapid induction of anaesthesia, with anaesthetists occasionally erring too greatly on the side of caution with doses that are too low.
Cardiothoracic surgeries also had a higher rate of AAGA, at around twice the rate of other surgeries.
Female gender, youth, obesity, a junior trainee anaesthetist and the use of neuromuscular blockades were found to be the key risk factors for AAGA.
Around 40% of victims of AAGA reported ongoing adverse effects, including nightmares, flashbacks and other PTSD-type symptoms.
The review authors say that although in many cases the cause of AAGA is obvious, involving technical failure or error, there remain cases where no rational explanation can be found. But although case reports of AAGA can make for harrowing reading, litigation is relatively rare. In the UK between 1995 and 2007, only 99 claims were made for intraoperative paralysis or brief awake paralysis.
When AAGA is reported, the authors recommend three stages of management: a meeting and interview with the patient; analysis of what went wrong; and follow-up interviews 24 hours and two weeks after the event.
It’s important that the interviewing clinician shows empathy, accepts the AAGA story as genuine, expresses regret, and offers psychological support to the patient.
You can read the review here.