Here's a patient in intensive care. She is short of breath and feverish, shivering but hot to the touch—likely symptoms of infection. The lab needs to culture her blood to find out, and if she is infected, doctors will base the choice and amount of antibiotic on the type of bug and the extent to which it has multiplied in her bloodstream. So blood is drawn for culturing, as it is hundreds of times a day in large hospitals. Her treatment may be difficult, even touch and go if the infection is dug in, but at least it will start with this routine step.
Routine? Maybe not. A study in the September issue of Mayo Clinic Proceedings suggests the very real possibility that far too little blood is being drawn. That could trick doctors into thinking the concentration of organisms is lower than it is. Patients might get less medication than they need. The bug could fight it off, putting the patient's life in jeopardy and perhaps generating an antibiotic-resistant strain that could threaten other patients.
Drawing blood for a culture should be routine. The amount recommended in current guidelines is 10 milliliters, or about 2 teaspoons. For every milliliter below that, the harvest of organisms falls by 3 percent. But when researchers surveyed several hundred physicians, nurses, and technicians at Henry Ford Hospital, a large academic center in Detroit, asking how much blood should be collected for a blood culture, almost 80 percent cited a quantity below 10 mL; 44 percent said less than 5 mL, and 21 percent said 1 mL or less.
Years of experience made little difference in the responses. Neither did working in an ICU. Or being a nurse or technician rather than a physician. "Our findings reveal that a high percentage of healthcare personnel do not know the optimal volume of blood recommended for collection," the authors wrote, adding, in traditional dry journal understatement: "[T]hese findings raise an important quality assurance issue."
You bet they do. Now, it could be that Henry Ford's caregivers are not typical of those at other hospitals. I can only say that I've been there, met many of them, and if anything, they aren't typical because they're better. I suppose it's also possible that they may have responded one way to the survey but follow a different standard in practice. That just doesn't seem logical.
Could it be that something so simple and basic is a factor in the distressing spread of hospital infections?