The enigmas that live inside your head
It’s a question that has plagued philosophers for centuries: what exactly is consciousness?
Anaesthetists — the people whose job it is to take consciousness away from us — tend not to worry about it so much.
You might think that’s because they’re practical people, focused on the job at hand rather than more abstruse philosophical questions. But it may be because they actually have no idea how to answer the question.
The astonishing thing is that, while we know (more or less) that anaesthesia works, we don’t really know how or even exactly what it does.
Inspired partly by her own fear of surrendering to the moonless night of anaesthesia, Melbourne journalist Kate Cole-Adams has spent more than a decade investigating the practice she calls “the most brilliant and baffling gift of modern medicine”. The resulting book, Anaesthesia, is not just an account of medical research but a poetic exploration of the mysteries of the human mind.
Every day, anaesthetists put hundreds of thousands of people into chemical comas, ColeAdams writes, allowing “the body’s defences to be breached in ways previously unimaginable except during warfare or other catastrophe”. Through the use of powerful poisons, [anaesthesia] has enabled entry into the secret cavities of the chest and the belly and the brain. It has freed surgeons to saw like carpenters through the bony fortress of the ribs. It has made it possible for a doctor to hold in her hand a steadily beating heart.
It is, as Cole-Adams says, mind-blowing. And yet, just how our minds get blown away, and then brought back again, remains a mystery even to those who perform this manoeuvre on a daily basis.
Although she is at pains to assert that modern anaesthesia is remarkably safe, Cole-Adams does not appear particularly reassured by the response of some anaesthetists to her questions about how the whole thing actually works: you don’t need to understand how an engine works to drive a car.
Modern general anaesthesia relies on a cocktail of mind-altering drugs, which act in different, not always predictable, ways on different parts of the brain. The three main elements of the cocktail are generally: hypnotics to create and maintain unconsciousness; analgesics to control pain; and a muscle relaxant to stop the patient moving on the operating table.
“Different anaesthetists mix up different cocktails,” Cole-Adams explains. “Each has a favourite recipe. An olive or a twist. There is no standard dose.”
Hypnotics are powerful drugs and, at higher doses, lethal ones. “In blotting out consciousness, they can suppress not only the senses but also the cardiovascular system. Every time you have a general anaesthetic, you take a trip towards death and back.”
Most of us do, of course, make it safely back but, given the imprecision of the science, it’s not surprising anaesthesia doesn’t always go according to plan.
Cole-Adams speaks to people who have experienced “anaesthetic awareness”, the ordeal of being conscious during surgery but, due to the presence of a muscle relaxant in the anaesthetic cocktail, unable to signal that awareness to operating theatre staff. Patients can be left traumatised, haunted by memories of pain accompanied by utter paralysis.
Fortunately, such experiences are rare … as far as we know. Hypnotic drugs are also powerful amnesiacs, raising questions about whether anaesthetic awareness may be more common than we realise, but rarely remembered once we emerge from our induced coma.
Even if we do remain unconscious throughout the procedure, could trauma at some level remain imprinted on us, Cole-Adams wonders, and how might that affect us in the life after anaesthesia? Might we experience ongoing emotional “memories” without consciously understanding their source?
British neurosurgeon Henry Marsh is another writer who has grappled with the mystery of consciousness, and its opposite, in his case from the perspective of someone who has spent his life cutting into living human brains.
“There are one hundred billion nerve cells in our brains,” he wrote in his bestselling first memoir, Do No Harm. “Does each one have a fragment of consciousness within it? How many nerve cells do we require to be conscious or to feel pain? Or does consciousness and thought reside in the electrochemical impulses that join these billions of cells together?’’
Cardinal George Pell is under intense pressure; facing page, Pell in Rome during the royal commission