A student was choked by blood clots in her lungs just four hours after a doctor had sent her home and told her to take a Lemsip.

Penny Oldfield, 24, from Eastbourne, collapsed within minutes of returning to her halls of residence but an ambulance crew who treated her for more than an hour decided she did not need to go to hospital.

They left her on her bed but within 15 minutes her faltering breathing stopped and she was unconscious and dying by the time a second crew was called.

Miss Oldfield had seen GP Dr Jane Weston-Baker at 10.30am on the day she died, suffering from shortness of breath and chest pains.

Her breathing improved during the consultation and the doctor concluded she had a chest infection and was suffering from anxiety over two presentations she was due to give.

She sent her back to the university with a note to exempt her from the presentations and told her to take Lemsip. She was already on antibiotics after seeing a different GP three days before.

Miss Oldfield was in her last year and planned to travel the world after finishing her degree.

The sports science student from the University of St Mark and St John in Plymouth, Devon, died from pulmonary embolisms.

An inquest in Plymouth heard these were blood clots which formed as deep vein thrombosis but then moved to her lungs and stopped her breathing.

She saw her doctor at 10.30am, the first ambulance arrived at 12.23pm and the crew stayed for one hour 17 minutes, and the second ambulance was called just 11 minutes later at 1.51pm.

The crew tried in vain to revive her and she was pronounced dead at Derriford Hospital, Plymouth, at 2.55pm.

Plymouth coroner Nigel Meadows - who recorded a verdict of death by natural causes - said he had dealt with more than 20,000 deaths but had only come across deep vein thrombosis three times.

He said the condition was so rare in a fit young woman that the doctor and paramedics could not be blamed for failing to spot it.

Her mother Sue Taylor said there was a history of blood clots in the family and she, her sister, father and uncle had all suffered from clots or DVT.

She said: "Penny was a very outgoing person. If there was a party going she would be there. She loved life and encouraged others to do so."

After the inquest she said: "I just want people to learn from this tragedy. Plymouth is a university city and there are a lot of young people here.

"It is important we all realise young people get ill. They may not all have pulmonary embolisms but I want someone to listen and realise it is not always anxiety about their coursework."

Miss Oldfield had been ill for three days and had been to the doctor once before going again on the morning of her death suffering from breathing problems, her friend Emma Mannell said.

She said Miss Oldfield told her the doctor had told her to take Lemsip but then collapsed after returning to the halls of residence. An ambulance was called and after she was treated she recovered slightly and they helped her to her room.

Miss Mannell said: "The paramedics told me to talk to her and keep her calm and if she could keep it down to give her Lemsip.

"They left and I lay on the bed next to Penny. Her breathing was getting faster and she started to moan. Over a five-minute period she calmed down but then started to panic again triggered by her breathing.

"She stopped breathing, made a little gasp, and her right cheek turned purple. I could not keep her breathing going. I carried on for half a minute before I went to get help."

Dr Jane Weston-Baker said she rang Miss Oldfield and was so worried she asked her to come straight in for an emergency consultation.

She said when she arrived the student was very breathless but soon calmed down and her chest was moving normally with good air entry into both lungs.

The doctor told the inquest: "I took the view she had a viral upper respiratory illness and anxiety. We discussed breathing exercises and did some slow breathing.

"When she left the surgery she was not suffering from shortage of breath. I advised her to take Lemsip."

Ambulance paramedic Michael Rowe said he and a crewmate gave Miss Oldfield oxygen after being called to the halls of residence and at first thought she would need to go to hospital.

He said while they were there her condition and breathing improved and after he learnt she had already seen a doctor that morning he decided she was suffering from a virus. He left her in her room and was horrified when another crew was called out shortly afterwards.

He said: "It was with great shock that we returned to the same location and the same patient who was now in cardiac arrest.

"We were very upset about this incident. We went back to talk about it and the crews could understand why the decision to leave her was reached.

"None of us had ever attended somebody with serious pulmonary embolism before."

Recording a verdict of death by natural causes, Mr Meadows said: "People may look back and reproach themselves for decisions they made but it is hard for medical professionals who are doing their best all the time.

"That is not to say they made misjudgments or mistakes but that they made the best judgments they could at the time. Even if she had been admitted to hospital, with the best will in the world it is highly unlikely it would have prevented the ultimate fatal result.

"The family have my sincere sympathies. I would encourage any young person with a family history of DVT to bring it to the attention of their doctor."

Penny's sister Cassie Oldfield, 26, added: "She was a great girl, bubbly and outgoing, and very caring. She'll be sorely missed."

Cassie has raised almost £1,000 for the thrombosis charity Lifeblood by doing a skydive and organising a horse show. To find out more, go to www.thrombosis-charity.org.uk