Guidelines for the use of red blood cell transfusions may not be helpful to patients. According to a latest study, employing stricter guidelines for the use of red blood cell transfusions for patients subjected to cardiac surgery reveal similar rates of death and severe illness, than those provided with more transfusions. Apparently, transfusions have been previously linked with high rates of poor outcomes in severely ill patients.
At the time of the investigation, scientists initiated the Transfusion Requirements After Cardiac Surgery (TRACS) study to analyze the safety of a restrictive strategy of RBC transfusion in patients going through elective cardiac surgery. The study was triggered between February 2009 and February 2010 in an intensive care unit (ICU) at a university hospital cardiac surgery referral center in Brazil. 502 adult patients were subjected to cardiac surgery with cardiopulmonary bypass. These patients were randomly selected to undergo a liberal strategy of blood transfusion or to a restrictive strategy. While the liberal strategy included maintaining a hematocrit, of 30 percent or greater, the restrictive strategy had 24 percent or greater hematocrit. It is known that hematocrit is the volume percentage of red blood cells in whole blood.
Ludhmila A. Hajjar, M.D., Ph.D., of the Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo, Brazil, and colleagues noted that the overall average hematocrit values in the ICU was 31.8 percent in the liberal-strategy group and 28.4 percent in the restrictive-strategy group. A blood transfusion was given to 198 patients forming 78 percent, from a total of 253 patients belonging to the liberal-strategy group. Even from 249 patients in the restrictive-strategy group, 118 representing 47 percent were provided with a blood transfusion. After 30 days the primary composite outcome such as death from any cause, cardiogenic shock, acute respiratory distress syndrome, or acute renal injury requiring dialysis or hemofiltration during the hospital stay was calculated. Such results were apparently revealed by 10 percent patients in the liberal-strategy group and 11 percent of the restrictive-strategy group.
Authors presume that the number of transfused red blood cell units is a risk factor for clinical complications or death at 30 days. No major differences appeared in the occurrence of cardiac, respiratory, neurologic, or infectious complications, or severe bleeding requiring reoperation. Even no variations in lengths of ICU or hospital stay were reported. It was concluded that implementation of a restrictive transfusion strategy may not benefit, but increase costs and adverse effects related to RBC transfusion, like transmission of viral as well as bacterial diseases and transfusion-related acute lung injury.
The study was published in the October 13 issue of JAMA.