Ms Rayner was disappointed, however, because the hospital did not operate an autologous blood transfusion scheme. This process, where the patient's own blood is used, is already relieving pressure on donated blood stocks and improving recovery times for patients. However, 20 hospitals around the country are now using an even smarter method, called intra-operative salvage.
"What happens in most hospitals is that, when a patient loses blood during an operation, it is collected and poured away, which is an astonishing waste of a precious resource," says Dr Mike Thomas, a consultant in transfusion medicine and the chairman of the special interest group of the British Blood Transfusion Society.
During the intra-operative salvage process, blood is taken away by suction, as in normal operations, and is then fed through a tube to a machine which begins a washing procedure to make it ready for transfusion. The main advantage in patients being given their own blood is that it helps to avoid the efficiency of their immune system being reduced as a result of using somebody else's blood.
"The body does not recognise the donated blood cells as its own and does not accept them at first, and this allows bacteria to creep in by default," explains Dr Thomas. "Patients who have autologous transfusions are therefore less likely to develop post-operative infections and, on average, they leave hospital two to five days earlier than those who receive donated (or homologous) blood."
At Southmead Hospital in Bristol, a study of orthopaedic patients who had received autologous transfusions showed this to be the case, and the hospital's use of costly blood stocks and antibiotics has also been reduced.
Dr Carl Waldmann, the director of intensive care at the Royal Berkshire Hospital Trust, in Reading, says: "The introduction of intra-operative cell salvage has proved very beneficial as we now use less donated blood, which is very expensive - we estimate that donated blood costs around pounds 50 per unit [about a pint]. "Patients are comfortable in the knowledge that they will, in most cases, be given their own blood," he explains. "There is a genuine underlying concern among patients about the potential risk of exposure to HIV."
One patient who has felt the benefit of recycling his own blood is Stanley Yentis, aged 72, who lives in Heron Island, Berkshire. He was diagnosed as having an aortic aneurism, a potentially life-threatening condition, and went into hospital for a three-hour operation. During the operation he was given an autologous transfusion of around 12 units of his own blood.
"The doctor told me I would be given my own blood, but it didn't really mean much to me," says Mr Yentis. "I certainly had no problems with the system, and I felt fine four days later."
Mr Yentis developed no post-operative infection, the risk of which is higher in older patients, and was allowed home four days after surgery, whereas most patients recovering from similar operations have to stay in hospital for around 10 days. But Mr Yentis, a retired civil engineer, was riding his bicycle again within four weeks.
Dr Waldmann says that the most beneficial use of the process is in orthopaedics and vascular surgery. It is also used in emergency operations, although not all are suitable.
"The machine costs from pounds 10,000 to pounds 20,000, but once the hospital starts using it there are long-term cost savings in donated blood. But one problem, from the bureaucratic point of view, can be getting approval from managers to transfer money that would have spent on donated blood to buying a machine."
The National Blood Transfusion Service has warned that, in the run-up to Christmas, stocks of donated blood could fall to their lowest levels of the year. The service has urged donors to make a donation before the Christmas break. As people gear up for the festivities, attendances at blood transfusion centres fall sharply - although demand for donated blood rises due to an increase in road accidents and other injuries.
The Royal College of Physicians (RCP) has recently endorsed the mounting evidence of the benefits of autologous transfusion, and the message is filtering through to more doctors as shortages of donated blood become more common.
In its evaluation of intra-operative salvage, the RCP said that "provided a rigid standard operating procedure is in place and the equipment is easily available with appropriate staff training, the side-effects are fewer than those associated with allogeneic [donated] transfusion".
Until recently, the only option for patients who wanted to be given transfusions of their own blood was to find one of the few hospitals that has a pre- deposit scheme, in which patients give their own blood before a planned operation. Most hospitals found that this was too complex administratively and too expensive to run in terms of blood storage and nurse time. Nevertheless, the RCP predicts that pre-deposit schemes will become more widespread.
Which will be good news for Claire Rayner if she ever needs another operation. Ms Rayner, who is the chairwoman of the Patients' Association, says that she did not argue when she was told she could not pre-store her own blood.
"I was prepared to believe the reasons were good ones," she says. She had her operation but afterwards became anaemic and required a further blood transfusion. "I felt so ill, and it made a huge difference. I was so grateful to the person who made the donation. I thought about how they had done that for me, and it just hit me."
Ms Rayner welcomed the circular issued by the health department in consultation with the Patients' Association urging hospitals to do more to conserve blood.
"People have developed a bit of a thing about donated blood, which is unfortunate because it has saved thousands of lives. Collecting blood during surgery and putting it back sounds brilliant. It would be enormously reassuring."
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