Most people would turn into a quivering wreck faced with the sight of someone about to die of a stab wound – but not Jonathan Mackenny.

An Accident and Emergency registrar who has been working at the Royal London’s specialist trauma centre, he thrives on the challenge of having just minutes to save people’s lives.

Much of the fall-out from gang violence in Hackney and Islington is dealt with at the A&E unit in Whitechapel, and injured patients can be flown into the hospital’s helipad from as far afield as Essex.

One of the most famous trauma units in the UK, the hospital is unique in its provision of emergency care with state-of-the-art equipment, a resident consultant on hand 24 hours a day, seven days a week, and specialist teams which can be mobilised at the drop of a hat.

It all means trauma victims have a better chance of survival here than almost anywhere – as Jon puts it, “things happen quicker and slicker”.

The process to treat patients – who may have fallen from a roof, been attacked by another person or injured in traffic – begins with a pre-alert from ambulance HQ, providing notification that a trauma patient is on their way.

“They tell you the details briefly; it might say, ‘15 minutes away, stabbing, 24-year-old male and stable or unstable’ – which tells you how their body is responding,” explained Jon, who lives in Kingsland Road, Haggerston.

Signs of instability include dropping off into unconsciousness, a very fast heart rate or very low blood pressure and coldness of the peripheral limbs.

“If they are unstable it means that their body is coping badly with the amount of blood they have lost and there’s a likelihood you are going to have to do something very quickly to make them stable.

“Young people cope very well with losing blood until the last minute, old people cope quite badly at the start, so if it’s a young person who’s unstable, it means they are really critically ill.

“There’s certainly a golden hour where you have to get loads off things done, which means that in the first 20 minutes you have to address life-threatening problems,” he said.

An alarm will call the specialist team to assemble in A&E.

Senior A&E and intensive care staff, anaesthetists, surgeons, orthopaedic surgeons, specialist trauma nurses, and a radiographer all rush down and it’s Jon, or another senior doctor’s job, to direct them.

“If they are really, really ill when they come in, but they are still alive with their heart beating, they often need to be rushed straight to the operating theatre in order to stop the bleeding from wherever they are bleeding from,” said Jon.

“So if they’ve been stabbed in the tummy they could be bleeding from the liver or bleeding from the gut. There’s no point in pushing loads of blood into them because it’s still coming out, so you have to turn off the tap, that’s what they say.”

The job is stressful, but he’s learnt how to deal with it, and for Jon it’s what makes it exciting.

“Stress is good because it helps you focus, and it helps you to fully apply yourself,” he said.

“I think it’s normal for people to feel nerves in that situation, but you work through it in a protocol way, you address serious things with a framework that means you can’t go to pieces, and you have a team that supports each other.”

Although it’s rewarding to save people’s lives, it would be unsustainable to do that the whole time.

“You will go from a cough or a sprained wrist to someone who is almost expiring from pneumonia. You have to very quickly switch your tack as to how you deal with things. There’s a big swing in your stress levels throughout the day, but that means that I’m never bored,” he said.

It’s not surprising that studies have shown that the life expectancy of an A&E doctor is shorter than in other sectors and the shift work means high levels of burn- out. Many doctors will do their required stint and then go off to specialise in something else for a quieter life.

For this reason medical bodies and the government are trying to change the perception of emergency medicine to ensure high quality doctors choose to stay there for life. “It can be the most important department. It’s the front door and most visible part of the hospital, so you need to have a good team there,” said Jon, who remains fully committed to trauma medicine and the challenge of ensuring someone makes it back to the 100 per cent good health they enjoyed before their accident.

“Some people like being super specialised, but I think there’s a lot of value in keeping yourself as a broad generalist. I think it’s intellectually stimulating,” said Jon.

“In most jobs you narrow yourself down until you are good at one thing, so if you are a surgeon you might become an expert in one field of surgery.

“Some people find A&E unsettling because you never become a super expert at something. There’s an inherent amount of risk in putting yourself in there and you have to learn how to manage that and when to call for help, even when you are quite senior, because the people you will call for help from will be experts in what they do and you only do it for a short part of your day, maybe once every few weeks.”

Jon admits that when he chose to train in medicine he didn’t realise what he was letting himself in for, but he picked it above veterinary science because of the human contact it affords.

“It’s humbling when you get to speak to people and it’s a privilege to be involved in people’s lives in that intimate way, and it’s your hope you can help with what their problems are,” he said.