Pensioner Charles Rumsey won't be spending Christmas in hospital after a medical response unit from the Royal London arrived at his home in East Ham following a 999 call.
A district nurse advised Charles' wife Valerie to dial the emergency services when the 90-year-old's catheter was blocked.
Charles and Valerie, who have been living near Brampton Park for 53 years, were braced for a long day at A&E. But instead, the response unit arrived from Whitechapel and was able to change his catheter in their home.
"The response was so quick and arrived in 10 minutes after my 999 call," Valerie recalls.
"We got ourselves ready to go to hospital in an ambulance, but I was amazed when a car turned up with a doctor and an unbelievable amount of equipment.
"They examined Charles and said it could be done there and then. The doctor who unblocked the catheter sorted everything out so quickly."
It saved the trauma of a trip in an ambulance or having to spend time in hospital.
"Charles has advanced dementia," Valerie explained. "So it meant a lot not to have to leave the house."
Valarie is a former care worker who has been looking after Charles, a retired bricklayer, since he developed his condition.
The Physician Response unit carries medication, equipment and treatments usually only found in hospital, such as instant-result blood tests, urine tests and implements to stitch serious wounds. It also has a computer with access to medical records of patients like Charles, so the team can see hospital and GP notes. The mobile service takes doctors and medical equipment on the road treating patients at the scene or in their home which is saving the NHS £500,000 a year, a study has found.
NHS consultant Dr Tony Joy said: "Emergency departments and ambulance services are under pressure, but our response unit takes the emergency department directly to the patient for immediate treatment for those who would normally need to be taken to A&E.
"This also frees up hospital and ambulance resources and allows us to prioritise care in emergency departments."
The response unit at the Royal London is also saving around 1,000 ambulance trips a year, the findings by Barts NHS Heath Trust reveals.
The unit, the first in the country, is a collaboration by the Air Ambulance in Whitechapel and the London Ambulance services with Barts trust which runs the Royal London, Mile End, Newham University and Whipps Cross hospitals.
It answers 999 emergencies and dispatches a senior doctor and an ambulance clinician to treat illnesses and injuries at the scene or in the home rather than having to rush patients to hospital.
London Ambulance chief medical director Dr Fenella Wrigley said: "The response unit is saving an unnecessary trip to hospital, so that more ambulances are available for critically injured patients which reduces pressure on the NHS."
Nearly 2,000 patients were seen by the unit last year, more than five a day on average, with two-out-of-three being treated in the community including 1,000 likely to have been taken to hospital.
This reduced the number of days in hospital by 868 during the 12-month research, estimated to have saved the NHS £530,000. The savings were indentified over the year-long study, now published in Emergency Medicine Journal.
The unit was the first to be set up in the UK in 2001, when the air ambulance service was expanded from its initial trial run. The "surgeon response" concept is now being tested in places like Oxford, Lincoln and Wales, with other regions aiming to develop similar services.
Treatments carried out include head injuries, wounds, suspected infections or sepsis, delirium, falls, diabetic emergencies, breathing difficulties, urinary problems and palliative care.
London's Air Ambulance charity raises the funds for the rapid response cars and some medical gear on board, while Barts Health trust provides other equipment as well as training and the senior doctor who works half the time in the Royal London's emergency department and the rest with the response team.
London Ambulance Service provides the emergency ambulance crew from its 999 control centre in Bow.