I think that
surgeons have to understand that a blood transfusion is meant to be an
emergency measure to be generally avoided is possible. Even then it is also better to supply
moderate amounts forcing the body to quickly replace its own supply.
Otherwise it is
a surprise that this protocol is only now been called to task. It has been with us for decades from the
heroic days of battlefield medicine.
Obviously it is a practice that could benefit from empirical application
aimed at optimizing protocols.
We have
forgotten that blood transfusion is meant to be a heroic intervention that is naturally
risky even if no mistakes are made. It
needs to be dealt with respect and circumspection
Too much
blood: Researchers fear the ‘gift of life’ may sometimes endanger it
BY SHARON KIRKEY, POSTMEDIA NEWS JULY 12, 2013
Part 1
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 onto something?
In cases of massive “bleed outs” from trauma or
hemorrhage, or for patients with leukemia or other cancers, blood transfusions
can be lifesaving.
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 musthelp 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 of red blood cells,
and 102,000 doses of platelets, were transfused into patients outside Quebec in
2011-2012, according to estimates compiled by the Canadian Blood Services for
Postmedia News. (Hema-Quebec, which runs the province’s blood system, collected
252,340 units of blood from donors in 2011-2012; 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 the 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 province-wide 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 of patients 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, multi-organ 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. But
when they’re put into someone else, they can suppress the immune system.
More recent studies have shown that
transfusion-related reactions have fallen since blood suppliers began washing
white blood cells from blood. However, Dr. Aryeh Shander, clinical professor of
anesthesiology, medicine and surgery at Mount Sinai School of Medicine in New
York, says that while there has been an unquestionable reduction in fever rates,
“the rest is debated.”
Shander helped create the bloodless medicine and
surgery program at Englewood Hospital and Medical Center in Englewood, New
Jersey. He says that “old habits die hard” and that too many doctors believe
“something bad will happen” if patients don’t have a certain volume of blood in
their system.
—-
The biggest driver of red-blood-cell transfusions is
hemoglobin, the protein in red blood cells that ferries oxygen from the lungs
to tissues and cells throughout the body. Too little hemoglobin, and the person
becomes anemic.
Red blood cells are frequently transfused during
cardiac surgery, prostate surgery, joint replacements and in patients bleeding
from their intestinal tracts.
But, once removed from the body, red cells undergo changes
in their shape and function. Their membranes deteriorate; some cells burst,
releasing free hemoglobin, which mops up nitric oxide, the chemical that helps
blood vessels relax. There are now growing concerns that “older” red cells
stored for longer than a few weeks lose some of their ability to transport
oxygen — the very reason they’re transfused. In Canada, red cells are stored
for up to 42 days.
When he was in medical school, Ottawa critical care
specialist Dr. Paul Hebert, whose research has transformed transfusion
practices worldwide, was taught that seriously ill patients need a high level
of hemoglobin to keep diseased or damaged tissues alive. So ingrained was this
belief that anesthesiologists and surgeons routinely began transfusing surgery patients
if their hemoglobin dipped below a certain number (100 grams per litre of
blood.)
In a landmark paper published in the New England
Journal of Medicine, Hebert and his team found that patients who were only
mildly below that hemoglobin cutoff, but who were treated aggressively with
transfused blood nonetheless, were more likely to die, and had higher rates of
organ failure, than patients whose doctors held back until their hemoglobin
fell to lower levels.
“We found that, if
you give less blood, you do better,” Hebert said. “We think that’s because
many of the patients didn’t need it in the first place.”
In a study published in January 2013, Hebert and
co-authors reviewed 19 trials involving more than 6,000 patients that compared
higher versus lower hemoglobin thresholds in red-blood-cell transfusions. They
found that patients could be transfused at hemoglobin levels of 70 or 80 grams
per litre of blood without putting them at any increased risk for major
complications such as pneumonia, stroke, infection, or death.
If doctors were to use the lower thresholds, “I
think you can reduce blood use in many settings by at least half,” said lead
author Dr. Jeffrey Carson, chief of the division of general internal medicine
at Rutgers Robert Wood Johnson Medical School in New Brunswick, New Jersey.
A recent review of blood transfusions at three
Ontario hospitals found that the pre-transfusion hemoglobin levels were higher
than the recommended thresholds for many patients.
Some transfusion rates have been falling since the
province established a network of blood transfusion co-ordinators in 25
hospitals. A major thrust of the program is to treat patients with anemia — low
hemoglobin — before surgery “so that we avoid having to transfuse them when
they bleed,” said Dr. John Freedman, medical director of the program and
professor emeritus at the University of Toronto.
British Columbia created the first transfusion
registry in Canada in 1999; it remains one of the largest in North America. The
database tracks every unit of blood that gets transfused into someone in B.C or
the Yukon.
Within the year, The Ottawa Hospital hopes to have a
computerized system in place to capture where blood is going, which patients
are being transfused and their hemoglobin levels at transfusion.
While Jehovah’s Witnesses have taught doctors that
the body can compensate for extraordinarily low levels of hemoglobin, levels
that are too low mean the cells and tissues in the brain and other vital organs
become starved of oxygen.
Hebert has watched Jehovah’s Witnesses die for
refusing to be transfused, an experience that leaves the medical team feeling
helpless. “But you can’t force your values on someone else,” he says.
Hebert says more research and education is needed to
help doctors decide how long they can safely wait before ordering blood, how
much blood they should give and when to hold off giving any blood at all.
“The problem is that we don’t have the data,” Hebert
said. “In many cases, we just don’t know.”
Part 2
It is euphemistically known as “wrong blood in
tube”: a transfusion error that ends with a patient receiving blood meant for
someone else. Sometimes that patient is lucky and still gets his or her own
blood type. The error isn’t even caught.
In the worst cases, however, “mismatches” can kill
by causing a rapid and catastrophic reaction in which the person’s body starts
destroying the red blood cells almost immediately after infusion.
Death from an incompatible blood transfusion is rare
in Canada, but it happens. And every one is entirely preventable.
New Canadian research is raising fresh concerns over
the sheer magnitude of the frequency and types of transfusion errors that are
occurring, from the moment blood is ordered until the clamp on the IV is opened
to start the transfusion.
Experts say that while vast amounts of money have
been spent on making blood safer from infectious diseases since the
tainted-blood tragedy of the 1980s, too little has been done to make the actual
transfusion of blood safer.
The Public Health Agency of
Canada runs a surveillance system for transfusion injuries. The last
public report the agency issued was for 2004-2005.
That year, of the more than two million transfusions
documented, 762 “adverse events” were reported, including 11 deaths. Seventeen
cases of incompatible transfusions were documented; most involved red blood
cells. More than one-third of them were life-threatening.
The top three reported injuries were fluid overload,
where patients are given more blood than their bodies can handle, causing
swelling throughout the body or difficulty breathing; severe allergic
reactions; and serious lung injuries that can cause respiratory distress.
Overall in 2005, the risk of an adverse event was one in every 3,270 units
transfused.
Another government blood surveillance system — this
one tracking transfusion-related errors — identified 31,989 errors between
January 2005 and December 2007 among 11 participating hospitals. Nearly 3,000
errors, almost one in ten, were classified “high severity” errors with the
potential to cause serious harm, including death.
Experts say that the risks posed by transfusion
errors or adverse reactions to blood exceed the risk of contracting a virus
from blood by up to 10,000-fold, making it even more vital to avoid giving
blood in the first place to patients who don’t need it.
Yet researchers at Toronto’s Sunnybrook Health
Sciences Centre, who tracked transfusion errors over a six-year period at their
hospital, found that of 23 errors that harmed patients, virtually all involved
unnecessary transfusions.
In all, a total of 15,134 errors were reported over
72 months. For every error that harmed a patient there were 657 errors that
were detected and intercepted before the blood could reach the patient. “Wrong
blood in tube” — blood drawn from the wrong patient for matching
— occurred once in every 10,250 samples collected.
“One of the leading causes of major morbidity
(sickness) from a blood transfusion is just getting blood that wasn’t intended
for you,” said Dr. Jeannie Callum, director of transfusion medicine at
Sunnybrook.
This is how the error can happen: Two patients are
sharing a semi-private room. Patient A needs a blood transfusion. A sample of
blood needs to be taken to match the blood type with the donor blood. But the
nurse mistakenly takes the blood sample from patient B, and then puts patient’s
A name on the tube of blood that’s sent to the lab. Patient A ends up getting
transfused with Patient B’s blood type.
“Or, I’m a group O and someone inadvertently gives
me blood that was intended for the patient in the next bed,” Callum explained.
“I can have an incompatible reaction that puts me into kidney failure and can
threaten my life.”
Some “wrong-blood-in-tube” mistakes are hidden and
never caught because the patient is transfused with a blood type matching his
or her own. “Many times you may just get lucky,” said Dr. Alan Tinmouth, a
hematologist and scientist at The Ottawa Hospital Research Institute. The error
“doesn’t cause a severe reaction, or maybe the blood is still compatible.
Group O blood went to a group O patient.”
In cases where the blood is incompatible, some
people can survive receiving two units of mismatched red blood cells. Some die
after receiving one unit.
Even if transfused properly, blood is a biological
product, a liquid organ transplant, that can cause reactions,
particularly respiratory reactions, in recipients.
One of the major reactions is TRALI: transfusion
related acute lung injury, the leading cause of transfusion-related deaths. It
can happen with any type of blood product and often starts within an hour after
the transfusion begins.
Most cases occur when antibodies in the blood of
some donors react with incompatible proteins in the recipient, triggering an
immunological reaction. The person suddenly has trouble breathing. Fluid
accumulates rapidly in the lungs and blood oxygenation levels plummet. The
fatality rate ranges from five to 14 per cent.
“Everyone, when they think about transfusions,
always worries about infections, with good reason, (given) the tragedies that
happened in the 1980s,” Tinmouth says. Today, the risks of HIV and hepatitis C
from donor blood are so small, “we actually can’t measure them.”
But there are other risks, he said, including, with
platelets, the risk of bacterial contamination because platelets have to be
stored at room temperature. “And those bacterial infections can be very
serious,” Tinmouth said.
Callum, of Sunnybrook, says more needs to be done to
make sure that patients only get blood when it’s necessary and that the right
blood goes to the right patient, at the right dose.
Sunnybrook is bar-coding patients in areas with high
transfusion rates, including surgery patients. Handheld devices scan barcodes
on patient’s wristbands, then churn out labels at the bedside when a sample of
blood is drawn for matching. The patient ID band and the “bag tag” label on the
blood product are also scanned before the bag is hung, “and if they don’t match
an alarm goes off that says, ‘We’ve got the wrong patient here,’ ” Callum said.
Technologists at Sunnybrook are also scrutinizing
every order for blood for compliance with hospital guidelines. “We basically
block transfusions that should not be occurring,” she says. In “non-bleeding”
non-urgent cases, only one unit of red blood cells is issued at a time to make
sure no patient gets more blood than he or she needs.
Experts stress that serious, life-threatening
reactions are infrequent in comparison to the total number of transfusions. For
example, nine deaths were reported to the federal government’s transfusion
injuries surveillance system for the year 2006, for a rate of one death per
130,122 units transfused.
But 10 per cent of hospitalized patients receive
blood, Callum said.
“Sometimes when the patient has had a bad reaction,
we look back at how the patient was managed and we say, ‘did that patient even
need that blood product?’ ”
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