WHY THE GIFT OF LIFE CAN BE DEADLY
A growing body of research links blood transfusions with an increased risk of complications ranging from post-surgery infections to multi-organ failure and death. SHARON KIRKEY examines why experts now say the greatest threat to patients isn’t contracting
New research links blood transfusions with risk of infections, organ failure.
When doctors at a New Jersey hospital pioneered a “bloodless” surgery program for patients who refused blood transfusions on religious grounds, they discovered something totally unexpected: Jehovah’s Witnesses, who would choose death over a transfusion, recovered just as well as transfused patients — and in many cases, even better.
They suffered fewer post-surgery complications, spent less time on mechanical breathing machines and had shorter stays in intensive care.
Recently, doctors from the Cleveland Clinic in Ohio reported that Jehovah’s Witnesses who refused blood transfusions while undergoing cardiac surgery were significantly less likely to need another operation for bleeding compared with non-Witnesses who were transfused. They were also less likely to suffer a post-op heart attack or kidney failure.
Are the Jehovah’s Witnesses on to something?
In cases of massive “bleed outs” from trauma or hemorrhage, or for patients with leukemia or other cancers, blood transfusions can be life-saving.
At the same time, experts say there is remarkably little evidence to show which patients — short of those suddenly losing large amounts of blood — actually benefit from blood transfusions.
In fact, a growing body of research links transfusions with an increased risk of post-surgery infections, cardiac arrest, heart attack, stroke, kidney failure, lung injury, multi-organ failure and death.
Transfused patients spend more time in hospital than those who don’t get blood; they spend more time in intensive care units connected to ventilators; and have a higher risk of acute respiratory distress, where the lungs become saturated with fluid, preventing enough oxygen from getting to the lungs and into the blood.
Studies suggest that up to half of all red-blood-cell transfusions may be unnecessary. Needless transfusions not only waste blood, they expose patients to risks — including potentially life-threatening human errors that are occurring at every step in the transfusion chain.
Three decades after Canada’s catastrophic tainted-blood tragedy left 2,000 people infected with HIV and another 30,000 with hepatitis C, the greatest threat to patients today isn’t the risk of contracting an infectious disease from blood, experts now say.
It’s getting blood they don’t need.
From ancient times to the late 19th century, sickness was treated by blood loss: using lances or leeches to bleed the body of suspected diseases that caused “bad” blood.
Today, we call blood the “gift of life.” The belief that blood is almost a magical cure is still held by many.
“In the minds of many people, blood is life, and giving people blood must help life,” says Dr. Jacques Lacroix, a professor of pediatrics at the University of Montreal and a national and international pioneer in pediatric critical care and research. “But it does not work like that.” In fact, transfusions have been identified by the American Medical Association as among the top five overused procedures in medicine.
In Canada, about 850,000 units
‘In the minds of many people, blood is life, and giving people blood must help life. But it does not work like that.’ DR. JACQUES LACROIX, professor of pediatrics at the University of Montreal and a national and international pioneer in pediatric critical care and research
of red blood cells and 102,000 doses of platelets were transfused into patients outside Quebec in 201112, according to estimates compiled by Canadian Blood Services for Postmedia News. (Hema-Quebec, which runs the province’s blood system, collected 252,340 units of blood from donors in 201112; more than 526,000 blood products were shipped to hospitals.)
Canadian researchers have led the world in showing that patients benefit from more restrictive blood use. But, there is no single, unified national system to determine how much of the blood distributed by Canadian Blood Services is actually transfused, who gets it and whether it’s being given for the right reasons.
Studies suggest that, even when patients have the same underlying condition, the same surgery and the same blood loss, transfusion rates vary widely from hospital to hospital for the same operation.
For example, a review of more than 8,000 patients who underwent cardiac surgery in British Columbia between 2008 and 2010 found that the proportion of patients who received red-blood-cell transfusions ranged from 35 to 66 per cent.
A provincewide audit of Ontario hospitals published in May concluded that nearly one in three transfusions of frozen plasma — the liquid portion of blood that contains clotting factors to help control bleeding during surgery — was unnecessary.
In Calgary, knee replacement patients are being transfused at rates ranging from two per cent to 25 per cent, depending on the surgeon.
Many transfusions don’t meet even minimum published guidelines, experts say. Many patients receive not one, but multiple units of blood, increasing their risk of fluid overload, where the extra blood overwhelms the heart’s ability to pump it through the body. Transfusion-related circulatory overload is one of the leading causes of transfusion-related death.
In some areas of medicine, including cardiac surgery, no clear consensus exists on when patients should be transfused.
“What we are sure of, however, is that there is a huge variation in transfusion rates across Canada for cardiac surgery patients of the same risk profile, and this is very difficult to explain,” says Dr. Fraser Rubens, a cardiac surgeon at the University of Ottawa Heart Institute.
As concern mounts over the dangers of unnecessary transfusions, hospitals have begun using strategies to reduce the use of blood.
For example: ❚ Blood draining out from under surgical wounds is being siphoned off, re-processed and then re-infused back into the patient; ❚ Surgeons are using drugs to prevent bleeding and improve blood clotting; ❚ Surgeons are operating through laparoscopes and other minimally invasive tools to reduce bleeding from large surgical wounds; ❚ Patients are being screened and treated for anemia with supplements or drugs that boost the bone marrow to produce red blood cells before they get into the operating room.
The variability in transfusion rates is slowly falling. But doctors have been slow to adapt. “The biggest challenge is trying to change the behaviour of physicians,” says Dr. Alan Tinmouth, a hematologist and scientist at The Ottawa Hospital Research Institute. “People are being transfused at hemoglobin levels higher than they need to be.”
Many doctors remain unconvinced of the potential dangers of transfusions. None of the studies suggesting increased risks of harm prove cause-and-effect, just an association, they point out. What’s more, patients who are transfused tend to be sicker to begin with, so it’s no surprise that they don’t recover as well as non-transfused patients, they argue.
But Dr. Paul Marik says numerous studies have shown that the more blood given, the worse the outcome.
In a widely cited study published in 2008, Marik analyzed 45 studies involving nearly 300,000 patients. In 42 of those studies, the risks of red-blood-cell transfusions outweighed the benefits.
Transfused patients were twice as likely to develop infections, multiorgan failure and acute respiratory distress than the non-transfused.
Critics of his conclusions say many of the older studies were done before white cells were filtered out of whole-blood donations. White cells in the “host” body help fight disease and infection.