Dialing back transfusion triggers
Even high-risk patients do better with restrictive strategies
by Paula S. Katz
Published in the April 2012 issue of Today's Hospitalist
MORE EVIDENCE IS IN on transfusion levels for high-risk postoperative patients, and it's about to make your life easier.
Until now, the indications for postoperative transfusion have been controversial and the evidence spare. Add in the need to have a meeting of the minds with surgeons, and knowing when to transfuse these patients became even murkier.
"Doctors are all over the place in terms of what hemoglobin number to use," says Jeffrey L. Carson, MD, lead author of a new study that explored whether liberal or restrictive use of transfusions affected outcomes for
these patients. "Many clinicians believe if a patient has underlying heart disease, we should keep counts higher because patients will be less tolerant of anemia."
|"Less is OK and safe."|
–Jeffrey L. Carson, MD
Robert Wood Johnson Medical School
However, the study, which was published in the Dec. 29, 2011, New England Journal of Medicine (NEJM), found that the group given less blood did just as well as the group that got more.
Knowing that there is no demonstrated advantage to giving more blood to these patients—a conclusion that Dr. Carson has helped develop into guidelines published last month in the Annals of Internal Medicine—allows hospitalists to make more informed decisions and more authoritatively discuss options with surgeons.
This trial shows that in elderly patients with underlying cardiovascular disease, physicians can withhold transfusion down to 8 grams or until patients have symptoms such as low blood pressure," Dr. Carson says. "I think this finding could change practice."
When less is more
The Transfusion Trigger Trial for Functional Outcomes in Cardiovascular Patients Undergoing Surgical Hip Fracture Repair (FOCUS) targeted a high-risk group of patients for whom anemia would be harmful. The mean age of the 2,016 patients was 81. The group that got less blood got only one-third the amount: 600 vs. 1800 units.
Patients in the restrictive group didn't get blood unless their hemoglobin dropped below 8 grams per deciliter or they had symptoms that required it, such as cardiac chest pain or development of congestive heart failure. The most common symptom was persistent rapid heart rate or low blood pressure despite the administration of adequate fluid.
"That was evidence that this patient was not tolerant of that level of anemia and needed blood," says Dr. Carson, who is chief of the division of general internal medicine at Robert Wood Johnson Medical School in New Brunswick, N.J. He was also the study chair of FOCUS.
The study showed no difference in outcomes—death or the ability to walk across a room at 60 days—for these patients, whether they were on liberal or restrictive transfusion protocols. (The liberal transfusion threshold was hemoglobin of 10 grams per deciliter.) The results echo the conclusion of the only other large trial comparing restrictive to liberal transfusion strategies in critically ill patients. That study, published in the Feb. 11, 1999, NEJM also found that the restrictive strategy is "at least as effective as and possibly superior to a liberal strategy in critically ill patients, with the possible exception of patients with acute myocardial infarction and unstable angina."
"What's been happening over the last five years is a trend toward using less blood, but there's still great variation in practice," Dr. Carson says. "I think FOCUS will provide that confirmatory evidence that less is OK and safe."
For Dr. Carson, the key takeaway from the study comes down to quality of care.
Not giving blood unless it's necessary reduces the negative outcomes that can be associated with transfusions. Many of those outcomes are rare, he says: HIV, hepatitis C or hemolysis. But hospitalists, he notes, see the more common problems like transfusion-associated circulatory overload.
"There's a low—but real—risk of complications," he says. "If a strategy doesn't show that it improves outcomes, why would you ever use it?"
Using less blood also saves transfusion costs. According to Dr. Carson, that includes $250 to $300 per unit of blood plus related costs for nurses and other personnel.
To help build consensus on when to transfuse high-risk patients, Dr. Carson suggests that hospitalists consider participating on their hospital's transfusion committee to help set policy.
He also recommends taking a step that may be out of some hospitalists' comfort zone: sharing the study results with surgeons. Selling points for the findings, he notes, should include the fact that more than 2,000 patients were involved, and that the study included very old people with heart disease.
"I think once they see the data, they'll say, 'OK, now there have been two large trials in NEJM. Both say 7 to 8 grams is fine,'" he says.
Generalizing the results?
As to the study itself, Dr. Carson notes that researchers originally had to contend with an underwhelming recruitment of participants. As a result, the study expanded its criteria about a third of the way into the trial. It included not only patients who had had a history of cardiovascular disease, but also patients who had risk factors for it.
Having a slightly lower risk group of patients translates into having slightly lower event rates, Dr. Carson says. However, he feels it didn't have much of an impact on his results.
In fact, he says the results can be generalized to other groups of surgical patients who are likely to have an even lower event rate, given that the study focused on those most likely to have negative effects. "So if blood was going to make a difference," he explains, "it would have."
Dr. Carson gives the example of a patient with a GI bleed who is no longer bleeding at 8.5 grams. Do you need to transfuse up to 10 grams? "My view is that it's probably fine not to transfuse that group because they're not that dissimilar from patients from FOCUS," he says.
However, he notes that the results don't apply to patients with acute coronary symptoms. To determine if blood will make a difference to those patients, Dr. Carson is working on a pilot study for a clinical trial called myocardial ischemia and transfusion (MINT).
The NIH-funded study just finished enrolling patients and is expected to have results in May.
While having the new evidence makes it easier for physicians to make transfusion decisions, Dr. Carson cautions that individual patients have different tolerance levels for anemia. The trial shows only the average effect.
"In the end," Dr. Carson says," physicians have to evaluate patients individually and tailor treatment to what we know not only from medical research, but also from the specific needs of that patient."
Paula S. Katz is a freelance health care writer based in Vernon Hills, Ill.