Too many patients entering hospitals because of a heart attack may be leaving with anemia, a new study finds. The cause, it seems, is not vampires in the ICU, but an excess of blood drawn for laboratory tests.
The study, appearing in the Archives of Internal Medicine, analyzed data from nearly 18,000 patients in hospitals due to a heart attack, from 2000 to 2008. To begin with, it found that 20 percent of heart attack patients who didn t have anemia when entering the hospital developed moderate to severe cases of red blood-cell deficiency by the time they left. It turns out that the average volume of blood drawn from these patients (about 175 mL, or, half the size of a Starbucks tall) was more than double the amount drawn (about 85 mL) from those who didn t develop anemia, and there was a clear relationship between the quantity of blood drawn and the presence of anemia. Since anemia is associated with worse health outcomes in patients who have already suffered heart attacks, this should be avoided whenever possible.
The authors recommend that hospital staff be more aware of the amount of blood they re drawing from a patient over the course of a hospital stay. Dr. Stephanie Renake, an assistant clinical professor at the University of California, San Francisco, responded with commentary to the study, advising that testing from a single blood sample each day (as opposed to multiple samples) could significantly lessen the risk of inducing anemia in these patients.
ACSH's Dr. Gilbert Ross agrees. He notes that people with acute heart attacks are under more stress, which does have an inhibitory effect on the production of new red blood cells. No doubt, he says, we need to be more attentive to how much blood it's truly necessary to draw from these patients.