On 8th January 1989, a British Midland Boeing 737-400 departed from Heathrow bound for Belfast. Shortly after take-off, a fire broke out in one of its two engines. While trying to make an emergency landing at East Midlands airport, the pilots shut down the wrong engine and the aircraft crashed into an embankment on the M1 motorway, near the village of Kegworth in Leicestershire. 47 people died and 74 suffered serious injury.
The ‘local rationality’ for shutting down the wrong engine – i.e. the reason it seemed like a good idea at the time – had several contributing factors, but a key element was failure to correctly read the vibration indicator. Essentially, if you throw a piece of scrap metal into a jet engine (a fair summary of what happened that day) then it will vibrate like crazy, and this is registered on one of the dials in the cockpit. Stress, confusion, and – crucially – a recent redesign of the vibration gauge meant the pilots failed to recognise it. The correct answer was staring them in the face, but they missed it.
Fast forward 31 years. Glenda Logsdail died during anaesthesia for appendicectomy as a result of unrecognised oesophageal intubation (UOI). The breathing tube was placed in the oesophagus rather than the trachea, and the anaesthetist failed to realise this until it was too late.
UOI is a stubborn problem that officially kills at least six patients per year in the NHS, a figure widely believed to be a major underestimate. It is the focus of huge efforts by the Royal College of Anaesthetists and others, but persists despite awareness campaigns, training, and guidelines.
By overwhelming consensus, the key to detecting oesophageal intubation is in the correct interpretation of the capnograph trace, the device measuring carbon dioxide in the exhaled gas mixture. But the capnograph is just one of half a dozen different waveforms displayed on a typical anaesthesia monitoring screen.
During Mrs Logsdail’s inquest, it was revealed that at least one doctor present thought there was a good CO2 trace because they were looking at the wrong line on the monitor. And it is not the first time this fatal error has been made
The correct answer was staring them in the face, but they missed it.
How could such a catastrophic error happen? A better question would be “how often?” As a wise man once said, no-one with something important to say willingly runs the risk of being misunderstood. During airway management, the capnograph has something critically important to say, yet we willingly let it be misunderstood by hiding it in the randomly-arranged spaghetti of monitoring waveforms, with different positions, colours, shapes, and sizes. As demonstrated by Shepherd et al, despite there being an agreed standard arrangement there are at least 36 different configurations of capnograph display in operation in the UK, and in some cases up to 13 different versions are in use in the same hospital.
This is an absurdity that shames everyone in a position to fix it.
We shouldn’t be having to make the case, in 2026, for standardisation as a safety tool. We shouldn’t be having to spell out all the mental tricks that stress and task overload can play on those battling with a medical emergency. We shouldn’t have to explain ‘mind lock’ or confirmation bias.
Yet there are still those, many well-trained, some in positions of influence, who see standardisation as unimportant, or even harmful. Some view it as a threat to their autonomy, or some sort of cognitive barrier. These are disastrous, antediluvian attitudes that should not be tolerated, let alone promoted.
The failure to standardise waveform capnography is especially egregious, since in most cases it could be achieved with a simple software update, and zero ongoing cost. If we can’t standardise this, we can’t standardise anything. The only barrier is a lack of seriousness.
The Kegworth disaster was key milestone in aviation history: it was the last time anyone died through accident on a British-registered commercial aircraft. This safety record was earned through the diligent application of established human factors science. Since Kegworth, at a conservative estimate, medical error has claimed the lives of three-quarters of a million patients in the UK, and yet we are still prevaricating over those same principles.
The capnograph trace should be solid-fill, white, and at the bottom of the screen, everywhere. This doesn’t feel like asking for the moon on a stick.
So if you’re a member of Council of the Royal College of Anaesthetists, you could think about making compliance a condition of ASCA accreditation. If you have influence at the Difficult Airway Society or the Association of Anaesthetists, you could consider making some bold statements in support of standardisation. If you work at the MHRA or ISO, think about codifying this patient safety open goal into a national standard.
Failing that, if you’re an equipment manufacturer who’s prepared to do the right thing without being forced to, you could modify the software as standard and offer to carry out upgrades for your existing customer base. In which case, write and tell us and we’ll give you a shout out for your contribution to safety.
And if you work for an equipment manufacturer who can’t do this or doesn’t believe that it’s worthwhile, look in the mirror and ask yourself if you should be working for a different company.