An octogenarian could save thousands of lives with an invention that was inspired by his late wife.

Engineer and inventor David Jones, of Clayton Avenue, Hassocks, devised a monitor to warn patients suffering from Chronic Obstructive Pulmonary Disease (COPD) when they are not receiving enough oxygen.

The 81-year-old's brainwave is a tribute to his wife, Heather, who died after a lack of oxygen weakened her heart.

He has trialled prototypes of the gadget at the Princess Royal Hospital, in Haywards Heath, and now he is looking to market it in the US and Europe.

He said: "It gave me something to get my mind off the tragedy of my wife suffering. I'm very excited about it. It will save a considerable number of lives."

Mr Jones, who has a Phd in Electronic Engineering and has lectured at universities, noticed the need for an oxygen monitor when his wife was in hospital with COPD. He said: "I was called in because staff thought she didn't have much longer to live. When I got there I spotted the tube attaching the oxygen to the mask had come off. When I put it back on, she made a full recovery. It made me think there wasn't an adequate method of alarming the patient or staff if there was a problem."

Despite her recovery, oxygen deprivation placed a strain on Heather's heart and she died nine months later in 2006 of lung complications.

With the help of two neighbours, Noel Poncelet and Dr James Graham, the three devised a model, which stores up information about a patient's breathing and alerts them when they are not breathing properly.

The trio set up Oxymon Ltd and obtained a provisional patent in the US and Europe for the gadget.

They received a £20,000 grant from the South East England Development Agency and financial backing from two private investors helped pay for 40 prototypes.

Tests were carried out at the Princess Royal Hospital under specialist Mark Jackson, who has deemed the prototypes a success.

COPD affects sufferers by restricting airflow to the lungs. The killer disease is rapidly gaining on cancer as one of the most common causes of death among the elderly.

If distributed among medical centres and hospitals, the gadget could save thousands of lives around the world.

The neighbours are now seeking marketing support and they are hoping to call on Dragon's Den star James Caan for help. Mr Jones said: "I am a member of Sussex Enterprise which is offering three business inventions the chance to win marketing advice from the multimillionaire. I'm hoping our invention will be one of the three. Marketing is the hardest bit. It doesn't come naturally to an inventor."