He fell into the Medway in Maidstone twice while kayaking early on the morning of April 13. The second time his temperature fell from 37C to 23C, stopping his heart. He was too cold for it to be restarted with a defibrillator.
Mr Curtis, an accountant and amateur endurance athlete, was rescued by a friend, who performed chest compressions for 10 minutes until paramedics arrived. He was then flown to King’s, in south London, to save his life.
He said: “I remember falling out the first time, but I don’t remember falling out of the boat a second time at all. The next thing I remember was waking up in hospital four days later.”
He said his recovery was “miraculous” and praised the “world-class care” he received at King’s. Doctors said his extremely low body temperature was akin to an avalanche victim.
“It’s both absolutely incredible and remarkable,” Mr Curtis said. “I consider myself incredibly lucky that all of the steps fell into place. If anything in the ‘chain of survival’ had gone slightly differently, I wouldn’t be here now.”
Mr Curtis, from Gillingham, was kept alive with a mechanical chest compression system during his journey to hospital in the Air Ambulance Kent Surrey Sussex helicopter.
Mr Curtis is one of 1,000 patients to be transferred to King’s by air for life-saving treatment since its helipad opened five years ago.
On arrival he was put on an extracorporeal membrane oxygenation (ECMO) machine, which takes over the work of the lungs and heart, for “blood warming” treatment.
Doctors say this pioneering technique – also known as extracorporeal CPR (eCPR) - would probably have been used on Danish footballer Christian Eriksen had he not responded quickly to being shocked with a defibrillator when he collapsed during a Euro 2020 game this month.
Dr Georg Auzinger, consultant in critical care and director of the ECMO Service at King’s, said there was a gap of about two hours between Mr Curtis suffering the cardiac arrest and being put on the ECMO machine.
Normally there is a 25 per cent increase in mortality for every 10 minutes a patient’s heart cannot be restarted beyond a 30-minute window. After 60 minutes, there is a grave risk of the patient suffering brain damage.
He said: “You may get the heart back — we have had patients who have had CPR for more than two hours and the heart restarted — but sometimes it is too late for the brain.
“The big difference in Paul Curtis’s case was that his body temperature was very, very low.”
“His heart was basically not pumping for about two hours until he arrived at King’s. We then, based on the temperature, made the decision to go ahead despite the two hours and put him on ECMO, which took us another 20-25 minutes.
“Then his heart wasn’t beating still for roughly another hour. But at that time we had him on the machine and all the organs were supplied with oxygen.”
Several London hospitals – King’s, Bart’s, St Thomas’s and Harefield - perform e-CPR. King’s has used it on 41 occasions, of which about 40 per cent have survived. Dr Auzinger said this was a good outcome as the patients had effectively been brought back from the dead.
Mr Curtis’s partner Christine Cordle, a community nurse, said, “It’s a miracle Paul is with us today. If just one link in Paul’s chain of survival – which included his friend who first administered CPR, the paramedics, air ambulance, A&E and critical care unit at King’s – had broken he wouldn’t be with us now.”