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”
Villanueva C, Colomo A, Bosch A, et al. Transfusion Strategies for Acute Upper Gastrointestinal Bleeding. N Engl J Med 2013; 368: 11-21
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
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
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
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
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
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