It is a high-stakes scenario for any surgeon: a 65-year-old male patient with a high BMI and a heart condition is undergoing emergency surgery for a perforated appendix.
An internal bleed has been detected, an anaesthetics monitor is malfunctioning and various bleepers are sounding – before an urgent call comes in about an ectopic pregnancy on another ward.
This kind of drama routinely plays out in operating theatres, but in this case trainee surgeon Mary Goble is being put through her paces by a team of researchers at Imperial College London who are studying what goes on inside the brains of surgeons as they perform life-or-death procedures.
Goble looks cool and collected as she laparoscopically excises the silicon appendix, while fending off a barrage of distractions. But her brain activity, monitored through a cap covered in optical probes, may tell a different story.
The researchers, led by Daniel Leff, a senior researcher and consultant breast surgeon at Imperial College healthcare NHS Trust, are working to detect telltale signs of cognitive overload based on brain activity. In future, they say, this could help flag warning signs during surgery.
“The operating theatre can be a very chaotic environment and, as a surgeon, you have to keep your head and stay calm when everyone is losing theirs,” said Leff. “As the cognitive load increases, it has major implications for patient safety. There’s no tool we can use to know that surgeon is coping with the cognitive demands of that environment. What happens when the surgeon is maxed out?”
In the future, Leff envisages a system that could read out brain activity in real-time in the operating theatre and trigger an intervention if a surgeon is at risk of overload.
“If you really like listening to Whitney Houston, you could automatically play calming music. Or it might alert the lead theatre nurse so that she manages the inevitable nonsense that happens in a theatre room,” said Leff. “It’s like Minority Report for surgery.”
More controversially, it might also be possible to use brain stimulation to augment a surgeon’s performance if they were losing concentration.
The cap worn by Goble uses functional near-infrared spectroscopy (fNIRS), a noninvasive technique to measure changes in blood oxygenation in the brain – a proxy for the underlying neural activity. Previously the team has shown that novices had greater pre-frontal brain activity than experienced doctors when performing surgery. They also found pre-frontal activity appeared to be disrupted more easily in doctors whose performance dipped during stressful situations.
The latest work is attempting to map out the fNIRS signatures of cognitive overload, when a doctor’s performance begins to dip because they can no longer cope with the influx of information and demands being placed on them. The study, using trainee surgeons, will track brain activity and surgical performance as progressively more demands are introduced. The simulated environment means that every movement of the laparoscopic instruments can be traced, and copper wires embedded in the silicon appendix detect if incisions are on target.
“You often don’t really see any external signs from people,” said Leff, adding that doctors stereotypically have a “don’t hesitate to cope” mentality.
After the run-through, Dr Goble, a surgical trainee at Kings College NHS trust and study participant, said her stress levels were soaring even though it was a simulation. “Surgery is a stressful environment,” she said. “On a night shift, when you’re by yourself and you have to deal with competing clinical priorities, it’s really easy to get really overwhelmed. I work on my breathing as a sort of concentration method.”
Simulated surgery is increasingly used in teaching at medical schools and so this kind of monitoring could be integrated into training to identify trainees who need more support, and to track progress, according to Leff. Future patient safety policies could also be informed by better evidence on how operating theatre environments affect performance, in a similar way to how findings on fatigue led to new rules on safe working patterns for doctors.
“I think if this is framed in a way that is about helping people become the best doctors they can be and that it’s about patient safety, the acceptance is greater,” said Leff. “The moment you try to use these things to say that someone is or isn’t capable, you start to run into problems.”
It is not yet possible to read out brain activity in real-time while surgeons operate – and this application is likely to be more than a decade away. But rapid advances are under way in brain-computer-interface technologies, including non-invasive helmets designed to measure brain activity in healthy individuals.
The Imperial team is also investigating the possibility of using a non-invasive technique called transcranial direct current stimulation (tDCS) to enhance performance. It involves a weak electrical current being passed between two sponge electrodes placed on the scalp – just enough to feel a slight tingling. Previously, they found that trainee surgeons learning to suture laparoscopically improved more quickly and reached a higher level of performance if they received tDBS while practising. Experienced surgeons did not see the same gains, however.
“When it comes to neuro-augmentation that’s certainly more challenging ground and people become more sceptical,” said Leff. “It’s an area that’s going to struggle to garner much support as you are talking about sending signals to someone’s brain. fNIRS is harmless monitoring of what’s happening and we have seen that’s way more acceptable to people.”
