What’s New in the Patient Safety World
February 2013
More Evidence Favoring Restriction of Transfusions
We’ve done several columns (see list at the end of this column) highlighting some of the
detrimental effects related to red blood cell transfusions and the trend toward
more restrictive transfusion strategies in many different scenarios.
Several more recent
studies have given further credence to the approach of more restrictive
transfusion practices. One randomized controlled trial compared the safety and
efficacy of a restrictive transfusion strategy to a liberal one in patients
with GI bleeding (Villanueva
2013). They found the probability of survival at 6 weeks was higher in the
restrictive-strategy group than in the liberal-strategy group. Moreover, the
frequency of further bleeding and the frequency of adverse events were lower in
the restrictive transfusion strategy group.
A somewhat more
controversial topic is that of transfusion in patients with acute MI or acute
coronary syndromes and anemia. It is fairly well known that acute MI patients
with anemia have poorer outcomes. Another recent systematic review and
meta-analysis showed that anemia is independently associated with a significantly
increased risk of early and late mortality in acute coronary syndromes (Lawler
2013). That might make one logically imply that interventions to correct
anemia (like transfusions) ought to improve mortality. But is that the case?
Previous studies have had conflicting conclusions. So Chatterjee and colleagues
just did a meta-analysis of studies on the effect of transfusions on mortality
in patients with acute MI (Chatterjee
2013). They concluded that blood transfusion or a liberal blood transfusion
strategy compared with no blood transfusion or a restricted blood transfusion
strategy is associated with higher all-cause mortality rates. The all-cause
mortality rate for transfusion during acute MI was 18.2% compared to 10.2% for
a no transfusion strategy. But there are numerous limitations in the Chatterjee
meta-analysis, as pointed out in the accompanying editorial (Carson
2013). Most importantly, most of the patients in the meta-analysis came
from observational studies rather than from randomized controlled trials. A
lack of patient level data to provide reasons for transfusion also makes it
highly likely that there were multiple confounding factors.
In our April 2012 What’s
New in the Patient Safety World column “New
Transfusion Guidelines from the AABB” we noted that the AABB (formerly the
American Association of Blood Banks) had just come out with new clinical
guidelines for red blood cell transfusion (Carson
2012). While those guidelines generally call for adhering to a restrictive
transfusion strategy (7 to 8 g/dL threshold) for many patients, they could not
recommend for or against a liberal or restrictive transfusion threshold for
hospitalized, hemodynamically stable patients with the acute coronary syndrome.
Bottom line: until we have a large randomized controlled trial we are unlikely
to have a definitive answer as to the best transfusion strategy in acute
coronary syndromes.
On the other hand, a
new study suggests that transfusions may reduce mortality in patients with
sever sepsis and septic shock (Park
2012). The authors did a propensity-matched analysis of a prospective
observational database in twenty-two medical and surgical intensive care units
in 12 teaching hospitals in Korea. Transfused patients had a lower risk of
7-day, 28-day, and in-hospital mortality rates than those not transfused even
after adjustment for other variables.
The newly updated Surviving
Sepsis Campaign guidelines for management of severe sepsis and septic shock (Dellinger 2013) do
mention use of transfusion in early goal-directed resuscitation protocols that
use a target hematocrit of 30% in patients with low Scvo2 during the first 6
hrs of resuscitation of septic shock. But once tissue hypoperfusion has
resolved and in the absence of extenuating circumstances, such as myocardial
ischemia, severe hypoxemia, acute hemorrhage, or ischemic coronary artery disease,
they recommend that red blood cell transfusion occur when the hemoglobin
concentration decreases to < 7.0 g/dL to target a hemoglobin concentration
of 7.0 to 9.0 g/dL in adults
Prior columns on potential detrimental effects related to red blood cell transfusions:
· March 2011 “Downside of Transfusions in Surgery”
·
February 2012 “More
Bad News on Transfusions”
·
January 2012 “Need
for New Transfusion Criteria?”
·
April 2012 “New
Transfusion Guidelines from the AABB”
References:
Villanueva C, Colomo
A, Bosch A, et al. Transfusion Strategies for Acute Upper Gastrointestinal
Bleeding. N Engl J Med 2013; 368: 11-21
http://www.nejm.org/doi/full/10.1056/NEJMoa1211801?query=featured_home
Lawler PR, Filion
KB, Dourian T, Atallah R, et al. Anemia and mortality in acute coronary
syndromes: A systematic review and meta-analysis. Am Heart J 2013; 165(2):
143-153.e5
http://download.journals.elsevierhealth.com/pdfs/journals/0002-8703/PIIS000287031200734X.pdf
Chatterjee S, Wetterslev J, Sharma A, et al. Association of Blood Transfusion With Increased Mortality in Myocardial InfarctionA Meta-analysis and Diversity-Adjusted Study Sequential Analysis. JAMA Intern Med. 2013; 173(2): 132-139
http://archinte.jamanetwork.com/article.aspx?articleid=1485987
Carson JL, Hébert
PC. Here We Go Again—Blood Transfusion Kills Patients? Comment on “Association
of Blood Transfusion With Increased Mortality in Myocardial Infarction: A
Meta-analysis and Diversity-Adjusted Study Sequential Analysis”. JAMA Intern
Med. 2013; 173(2): 139-141
http://archinte.jamanetwork.com/article.aspx?articleid=1485995
Carson JL, Grossman BJ, Kleinman S, et al. for the Clinical Transfusion Medicine Committee of the AABB. Clinical Guidelines.Red Blood Cell Transfusion: A Clinical Practice Guideline From the AABB. Ann Intern Med 2012; E-429 published ahead of print March 26, 2012
http://www.annals.org/content/early/2012/03/26/0003-4819-156-12-201206190-00429?aimhp
Park DW, Chun B-C,
Kwon S-S, et al. Red blood cell transfusions are associated with lower
mortality in patients with severe sepsis and septic shock: A propensity-matched
analysis. Critical Care Medicine 2012; 40(12): 3140-3145
Dellinger RP, Levy
MM, Rhodes A, et al. Surviving Sepsis Campaign: International Guidelines for
Management of Severe Sepsis and Septic Shock: 2012. Crit Care Med 2013; 41(2):
580-637
http://www.sccm.org/Documents/SSC-Guidelines.pdf
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