Jane McCredie: Memories removed

THE first thing I heard as I returned to consciousness after a surgical procedure a few years ago was a conversation about Antarctica.

In true nerd style, I felt the need to step in to correct an error made by one of the conversationalists in the recovery room. ‘There are no polar bears in Antarctica”, I said weakly.

Later, I commented to one of the nurses that I couldn’t believe those were my first words on coming out from under the anaesthetic.

She looked confused.

“But, Jane”, she said, “they weren’t your first words. Don’t you remember the conversation we had about your work? I asked you what you did and you told me all about it.”

My surgeon was later surprised to also learn I had no memory of his postoperative visit despite having asked him a number of questions and appearing perfectly lucid at the time.

We may not know precisely how anaesthesia works, but we do know one of its functions is to cause amnesia by disrupting the process of memory consolidation — sometimes in unpredictable ways.

This can raise difficult ethical issues, especially in those rare cases where things do not go according to plan and the patient unexpectedly becomes aware and forms traumatic memories while under anaesthesia.

The effects of this experience, which occurs in roughly one to two surgical patients in every 1000, have been compared to post-traumatic stress disorder. It can be particularly damaging when the patient is aware of everything going on around them but is unable to communicate that fact.

So would an anaesthetist who realised a patient was unexpectedly aware be justified in giving the patient a drug designed to prevent them remembering the experience?

Canadian bioethicist Dr Walter Glannon believes they might be, even in situations where it would be impossible to obtain the patient’s consent, such as when awareness unexpectedly occurred under general anaesthetic.

“Assuming that the drug was safe and effective, the anaesthetist would be acting to prevent potential harm to the patient from an unforeseeable state of affairs”, he writes in the Journal of Medical Ethics.

The ability to wipe out someone’s memory raises a clear risk of abuse — what if the memory was of an insulting comment or a criminal assault? Even when the intention is clearly benign, the act remains troubling.

Dr Glannon describes a case in which he suggests an anaesthetist was justified in giving propofol to prevent memory consolidation to a young woman having a biopsy under local anaesthetic.

The patient had become extremely distressed after accidentally overhearing a comment about her “really, really bad cancer”. Swift administration of the drug successfully removed the woman’s memory of the event.

The surgeon in that case, Dr Scott Haig, has written his own thought-provoking account of the incident and the mixed feelings it aroused.

His immediate response was gratitude to the anaesthetist for providing a reprieve, allowing the bad news to be delivered in a more considered and supportive way.

The theatre nurses’ eyes, however, expressed a different view: “ ‘How can you do that?’  they demanded to know. ‘Don’t you need consent or at least fill out some kind of form before you steal a patient’s last 10 minutes?’ ”

Writing more than a decade after the event, and several years after his patient’s death, Dr Haig was still grappling with the implications of such chemical manipulation of the mind.

“Everyone I know who deals with medicines that affect minds seems to operate with a very clear functional distinction between personhood — the realm of virtue, vice, responsibility and creativity — and brain chemistry”, Haig wrote. “That distinction was clear in the eyes of my nurses that day. Something more important than a chemical balance in Ellen’s brain had been violated — only a little and, obviously, with benevolent intent. But it hadn’t been as simple as pushing a rewind button. Something there had borne the unmistakable quality of wrong.”

Gaining consent in such a situation would be difficult — the patient was extremely distressed and the window for administration of a drug to prevent memory consolidation is narrow.

The removal of the memory may well have done the patient a kindness but, as Dr Haig acknowledged, removing another person’s memories without their consent is always going to feel like a violation.
 

Jane McCredie is a Sydney-based science and medicine writer

* Addendum 18 June 2014, by Dr Ruth Armstrong, medical editor of MJA InSight:

Research on the timing of any amnesic effect of propofol appears to be limited, although both the articles cited in the column suggest otherwise. We sought expert comment from a senior Australian anaesthetist, who concurred that, while midazolam (and to a lesser extent, other anaesthetics) have strong anterograde amnestic effects, it is doubtful that they have any retrograde amnesic effect, especially if given alone.