Even ‘minimal’ intraoperative transfusions can harm patients
MedWire News: The adverse effect of intraoperative blood transfusion extends down to transfusion of just 1 unit of packed red blood cells (PRBCs), report US researchers.
"The clear implication is that limiting intraoperative blood loss and blood transfusion may improve outcomes in certain patients," say Victor Ferraris (University of Kentucky, Lexington) and co-workers.
The findings emerge from the team's analysis of data from the American College of Surgeons National Surgical Quality Improvement Program database, involving 941,496 operations in 173 hospitals from 2005 through 2009.
Most patients (94.9%) did not require intraoperative transfusions, Ferraris et al report in the Archives of Surgery. Of the more than 48,000 patients who did receive transfusions, 31.4% received a single unit of PRBCs and 68.6% were given more.
The researchers analyzed the impact of transfusion on mortality and seven categories of morbidity: wound complications, pulmonary complications, renal complications, postoperative new neurologic events, myocardial infarction or cardiac arrest, sepsis, and return to the operating room within 30 days.
As expected, mortality and morbidity rose in line with the number of transfused PRBC units in unadjusted analyses. Overall, the mortality rate was 1.1% in patients without transfusions versus 6.3% in those given transfusions and the corresponding composite morbidity rates were 11.8% versus 34.6%. Morbidity was higher among transfused patients for all individual outcome categories.
Ferraris et al then matched patients who did and did not receive 1 unit of PRBCs based on a propensity score, generated from 55 preoperative variables, for receiving PRBCs. They found that the adverse effect of transfusion - of just 1 unit of PRBCs - remained for mortality, composite morbidity, and four of the seven morbidity categories.
The adjusted mortality rate was 5.2% among patients not given a transfusion versus 6.1% among those given 1 unit of PRBCs, and the corresponding composite morbidity rates were 30.1% versus 34.2%. Transfusion of 1 unit of PRBCs had a significant adverse impact on wound, pulmonary, and renal complications, and on sepsis, but not on neurologic and cardiac complications, or on patients' risk for returning to the operating room.
In an invited critique, John Holcomb (University of Texas Health Science Center, Houston, USA) argues that surgeons "use (or allow the use of) blood products much too freely in hemodynamically stable patients."
He says: "Usually we allow treatment for an isolated laboratory value rather than the entire patient, something we routinely tell our residents and students not to do."
Holcomb urges adherence to published guidelines, saying: "From a physiological point of view, replacing operative blood loss with 1 to 2 units of PRBCs does not make sense. From a quality outcomes and preventable injury viewpoint, Ferraris and colleagues have shown that these minimal transfusions injure our patients."
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By Eleanor McDermid