Tag Archives: anaesthesia

Lights, camera, action

We’ve got some great objects on display in our new exhibition – spiders, an Xbox, an anaesthesia machine, and more. These help to bring the stories we’re telling in Pain Less to life.

But pain is personal, and that has driven how we are presenting the stories in our exhibition. The objects we’ve found give a tangible link to our stories, but we want to introduce our visitors to the people behind them.

So we tore ourselves away from our desks, hopped on trains, planes and auto-mobiles, and headed off around the country to film interviews with the scientists and people whose tales we’re telling in Pain Less.

These films make up a key part of the exhibition, and you might have noticed over the last few weeks they have been appearing on the blog, but in case you missed them here they are… Enjoy!

Pain in the brain

Pain killers

Painfully unaware

Virtually painless

Advertisements

Painfully unaware

If you’ve ever had surgery, or simply had a tooth out, then you’ll know popping a couple of Ibuprofen just isn’t going to cut it, you want to be numb, or even better, unconscious… Enter the anaesthetists.

Medics have been using anaesthetic drugs for over 150 years and they have plenty of clinical evidence that they work extremely well. But how does anaesthetic actually work? And how much to we understand about what we experience when we lose consciousness?

During anaesthesia for major surgery, drugs prevent you being aware of painful sensations. Doctors often conduct minor surgery, and other procedures, under local anaesthesia, and use sedative drugs to calm you.

General anaesthetics and sedatives alter your state of consciousness. Anaesthetists commonly give them in combination with powerful painkillers to make sure your surgery is as painless as possible.

Today general anaesthesia often begins with an injected dose of the drug propofol. Researchers know a good deal about how this drug works on a cellular level.

‘Our cell research showed us that propofol influences receptors on certain nerve cells. These nerves normally respond to a chemical messenger called GABA that stops them sending signals. Propofol mimics the effects of GABA and inhibits nerve signals.’ says Jeffery L Barker from the Laboratory of Neurophysiology, part of the NINDS institute in Bethseda, Maryland

Propofol is only one of many different types of anaesthetic drugs. Each type appears to affect different sets of receptors in the brain, but they all make you lose consciousness.

Because some anaesthetic drugs influence different kinds of neuron compared with others, their precise effects on the brain may be very different.

Brain research tools can show which areas of the brain are affected by different anaesthetics. With fMRI (functional magnetic resonance imaging), for example, a scanner shows brain activity in 3D. On the other hand, when an EEG (electroencephalogram) is recorded, non-invasive electrodes are stuck onto your scalp to measure electrical activity on the brain surface.

EEGs and fMRIs can measure brain activity during different levels of consciousness: awake, asleep and even anaesthetised.

So what can today’s brain imaging technologies tell us about how anaesthetics work?

Steven Laureys leads the Coma Science Group at the University of Liège in Belgium. In an experiment he anaesthetised patients and scanned their brains.

‘Even when volunteers were unconscious, small “islands” in the sensory cortex of their brains showed activity in response to external stimuli,’ says Steven. ‘But this activity did not spread through the brain to areas that control behaviour and memory. This means that although your brain responds to sensations while you’re unconscious, memories don’t form as they would normally.’

Most people seem to have to no memories of sensations during surgery. But Jackie Andrade, Professor of Psychology at Plymouth University, has demonstrated that we’re able to form partial, ‘implicit’, memories under anaesthesia.

‘We tested patients by having them listen to certain words during surgery under general anaesthesia. When they came around, we found that the patients responded differently to words we had played while they were “unconscious” than to other words.’

There are two groups of patients with explicit memories of surgery: those who can remember pain and those who can’t. If you remember pain, you are much more likely to develop post-traumatic stress. But Jackie thinks that implicit memories may also affect you.

‘Although you’re not aware of these memories at all, they could affect recovery times after surgery and cause psychological stress.’

‘Implicit memory could be used to benefit patients undergoing surgery. Encouraging and positive comments made in the operating theatre could be used to reassure patients and reduce anxiety, even while they’re unconscious.’

So how can research improve future anaesthesia?… Do we just need better drugs?

Consultant anaesthetist Andrew Morley from St Thomas’ Hospital in London thinks new drugs are not the top priority.

‘Patients having surgery under anaesthesia in future will benefit more from small changes in all aspects of the process than from a single “miracle” anaesthetic drug,’ says Andrew.

‘Even if we don’t know exactly how they work, today’s general anaesthetics are highly effective. Before surgery, I consider both patient and planned operation in deciding the best combination of drugs and techniques. I aim to provide good operating conditions for the surgeon, minimising side effects and getting the best possible outcome for each patient. It’s a bespoke business.’

Could new technology be the answer?

The fEITER is a portable imaging technology that has successfully recorded 3D images from anaesthetised brains as they lose consciousness.

Brian Pollard, who developed fEITER the University of Manchester, explains:

‘These images gave us confirmation that losing consciousness involves changes in electrical activity deep inside the brain. Finding out about the process of anesthesia and sedation can help us monitor brain function in the operating theatre, and reduce the risk of painful awareness during surgery.’

But are high tech monitors alone enough to improve anaesthesia?

Emery Brown’s work at the Department of Anaesthesia, Massachusetts General Hospital and at the Department of Brain and Cognitive Sciences, MIT spans two disciplines: anaesthesia and neuroscience. He believes electroencephalogram (EEG) recordings allow anaesthetists to see when someone is unconscious and to understand how anaesthetic drugs create altered states.

‘Different drugs produce signatures that are readily interpretable using EEG. I can see signatures which indicate that the brain is unable to process information, which would mean that you are unconscious. In the future, we may be able to identify the brain circuits for consciousness and pain, and treat them directly using targeted drugs delivered to these circuits.’

Emery believes painful awareness can be prevented by training anaesthetists in neuroscience so they can interpret how EEG readings relate to underlying brain states.

‘The true culprit in cases of awareness is anaesthetists not being able to tell when a patient is unconscious. They often rely on brain activity monitors that are grossly simplified.

‘I can understand detailed raw EEG readings. If you came to me and told me you were afraid you were going to be aware during surgery, I would tell you that I can keep it from happening by keeping an eye on your EEG.’

It is clear to see experts are approaching this issue from all sides. But in the end it may all come down to the skilled experts in the operating theatre…

Andrew Morley explains, ‘Preventing painful awareness in surgery is not only about technology and understanding the brain.’ says Andrew Morley. ‘For decades, scientists and clinicians have tried to use the EEG – raw and otherwise – to distinguish conscious from unconscious patients reliably. No-one’s got it quite right yet – awareness still happens.’

‘Improving anaesthesia is also a matter of improving vigilance in the operating theatre and reducing the likelihood of human error. The Royal College of Anaesthetists and Association of Anaesthetists of Great Britain and Ireland are gathering information on real cases of accidental awareness during general anaesthesia. The results may help us progress towards a better practice and healthier patients.’

Are you conscious?

Count down from ten…

Have you ever been put under general anaesthetic before surgery? I have, and when the anaesthetist asked me to count down from ten, I got as far as eight before I was out cold. The next thing I knew, I was waking up in the ward, tonsil free, and looking forward to a two-week diet of painkillers and ice cream. Most of us assume that when the drugs knock us out, that’s it; we feel nothing until the effects of the drugs wear off. But is this really the case?

Andrew Morley is an anaesthetist. He regularly sedates patients for minor surgery. For this, he uses a general anaesthetic drug called propofol at a low, or ‘sedative’, dose. Under these circumstances apparently some patients respond to pain while they’re under.

‘Patients do appear to experience pain from time to time during procedures under sedation – I take their response as a prompt and give them painkillers and top up their sedation. Afterwards they very often have no memory of the pain.’

This suggests that we may experience pain during surgery even when under sedation, but not remember it after. If you can’t remember pain, does it matter?

Psychologist Jackie Andrade thinks it does:

‘You may be aware during surgery but not completely remember it. Partial or “implicit” memories of these situations might lead to psychological stress and longer recovery times.’

Questions like this, and the incredibly rare cases where patients remember specific events of awareness during major surgery under general anaesthesia, have prompted researchers to come up with new ways to measure consciousness to ensure we really are out for the count, when it counts.
Meet fEITER, a portable scanner that can project a real-time video of the brain’s activity as it slides into unconsciousness. Once anaesthetists understand exactly what this activity means, this new invention might help them to understand more about their patients’ awareness.

Unfortunately, there are only two of these scanners in the world and the scientists couldn’t spare one for a whole year for Pain Less.

But we have managed to get our object-handling gloves on one of these…

This is called a BIS monitor. I’ll leave it to our expert anaesthetist Andrew to explain:

‘This machine continuously records the electrical activity on the surface of the brain. It then analyses these “brain waves” using a mathematical formula to come up with a number that reflects the likelihood of the patient being conscious. Some anaesthetists use the monitor to adjust the dosage of anaesthetic drugs to keep their patient unconscious. Others are sceptical about how effective machines are at monitoring consciousness.’

I’ll be back soon with more stories of success (or disappointment) from the object quest.

Define the topic

Step one to create a new exhibition: define the topic.

Defining the topic is tricky. We started with anaesthesia, pain and consciousness – but that’s a huge area that spans a massive amount of research. It could fill a whole museum! We need to narrow it down, and pick the stories that grab the attention of our visitors and cover the very latest ground-breaking research.

So the first step is to research these topics. We partnered up with Andrew Morley, a consultant anaesthetist from Guy’s and St Thomas’ Hospital who, as part of this project, created a network of experts: scientists and researchers working at the cutting edge of research in pain, consciousness and anaesthesia.

With Andrew’s help we narrowed down this network to just over 60 leading experts. But this is still way too many research stories to fit into one exhibition. How do we select what to keep and what to leave out?

We turn to our two participatory groups: Year 9 students from Langley Academy, and a group of adult chronic pain sufferers. A handful of our leading experts came to meet the groups and to explain their research.

Of the three topics, ‘pain’ stands out as the most interesting for both Langley Academy and our adult group. How mood and emotion affect how we feel pain, the line between pleasure and pain, how we measure pain, and the emotional and psychological aspects of pain were the areas they engaged with most. Consciousness also prompted some lively discussion; do we really feel no pain when we’re unconscious, or do we simply not remember it?

The next step is probably the most challenging – to combine the new with the interesting to feature unforgettable stories that are newsworthy enough to entice our visitors to engage with the exhibition.

The ageing population is a massive issue that isn’t going to go away. Will new drugs be able to offer painless ageing? What are the implications of the mind-boggling, often pricey and potentially dangerous cocktails of drugs people take to overcome pain? Are we in danger of become addicted to pain medication? One in five people suffer with chronic pain. What about global medicine; how do those in developing countries cope without the expensive drugs?

The focus of the exhibition comes out of the following…

In the UK, on average we take 373 painkillers each year. They can be addictive or have side effects, so taking them isn’t great. But will the current research provide an alternative?

Our groups were fascinated with the idea of how personal pain is, how much it is governed by our mood, emotion and psychology, and why we all experience pain differently. How does the link between the brain and body influence the pain you feel? Will this understanding lead to a pain-free future?

Our experts and groups and some amazing individuals will help us to tell stories about this mind–body connection in our Pain Less exhibition.

Suzy’s loss…

A lot of great stories have to be thrown out when we define the topic of the exhibition. I asked Suzy Antoniw, the Head of Content, which was her favourite story that was lost – she had become very attached to some!

‘Did you know chilli can help numb pain? I didn’t until we started to research new pain treatments – apparently it’s very good at numbing painful nerve endings. Unfortunately we haven’t been able to feature it as a main content section because, while the molecule involved is very effective in the body, it has strong side effects in the brain. Our exhibition is all about how understanding the mind–body link is leading to new treatments – but the research in this area hasn’t quite managed to solve this mind/body problem yet. You never know, though, I may try and pop it back in when we write the in-depth content.’

So we now know what stories we want to tell. Hurray! Believe me, that was NOT a painless process (pun definitely intended). Next we need to get our hands on some great objects to bring the stories to life.