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Do Heart Surgery Patients Get Too Many Blood Tests?
The high number of blood tests done before and after heart surgery can sometimes lead to excessive blood loss, possibly causing anemia and the need for a blood transfusion, new research suggests. The study included 1,894 patients who underwent heart surgery at the Cleveland Clinic between January 2012 and June 2012.
A total of 221,498 blood tests were performed from the time the patients first met their heart surgeons until they left the hospital, for an average of 115 tests per patient, according to the study.
The most frequently performed tests were 88,068 blood gas analyses; 39,535 coagulation tests; 30,421 complete blood counts; and 29,374 metabolic panels. Phlebotomy volumes differed between intensive care unit and hospital floors, with median volumes of 332 mL and 118 mL, respectively. The cumulative median volume for the entire hospital stay was 454 mL (about 15 ounces).
The results of the study were published online January 9 prior to print in the March issue of the Annals of Thoracic Surgery.
“We were astonished by the amount of blood taken from our patients for laboratory testing. Total phlebotomy volumes approached 1 to 2 units of red blood cells, which is roughly equivalent to one to two cans of soda,” said study leader Dr. Colleen Koch.
The highest amounts of blood loss occurred among patients undergoing the most complex heart surgeries. The greater the number of laboratory tests and the longer patients stayed in the hospital, the more likely they were to require transfusions.
“Prior research shows that patients who receive blood transfusions during heart surgery have more infections after surgery, spend more time on the ventilator, and die more frequently—even after adjusting for how sick they were prior to surgery,” Koch said.
Patients should ask their doctors whether a specific test is necessary, she advised. Some questions she suggested include: What is the indication for the test? Will it change my care? If so, do you need to do it every day?
“They should inquire whether smaller-volume test tubes could be used for the tests that are deemed necessary. Every attempt should be made to conserve the patient’s own blood —every drop of blood counts,” Koch concluded.
Sources: Medical Xpress; March 2, 2015; and Annals of Thoracic Surgery; January 9, 2015.