Medical Myths: Fever = blood cultures now!

When I was an intern in a big old hospital one of the tasks we did was taking blood cultures off of patients who spiked fevers on the wards.  In fact thinking back on it, I think I was taking cultures to appease the senior ward nurses and not really stopping to think about the why?  Probably stabbed any number of patients with early sepsis and happily continued onto the next job without even worrying about the BP, lactate, line sepsis etc etc…  It was an annoying task as it was “time critical” – you had to get the cultures ASAP as the fever spiked – or else the boss would be grumpy, we might “miss the sepsis”.

Were we right to worry about getting the cultures done in a timely fashion?  Did it have to be “during the rigors?”

My colleague pointed out this paper by Riedel et al, Journ Clinical MIcro (April 2008).  This case-review looked at 1436 patients and their fever – culture timing profile and found that it really didn’t matter when you took the cultures in realtion to the spike of a fever – the majority of positive came from cultures taken hours after a fever.  This study cannot comment on the numbers of “missed” bacteremias as a result of wrong / delayed timing.

So what does it all mean for you, next time the nurse calls to tell you Mr Jones has spiked a temp….

  1. Walk, don’t run – it really doesn’t matter if you do it now or in an hour.
  2. Go there, look at the patient and think “what is going on here?”  Does he have a reason to be febrile already documented, on appropriate therapy?  Or, is he someone who needs to be reassessed for sepsis – does he have a line infection?  Does he have a wound infection?  Is he in SIRS or worse?  Do you need other sites cultured – urine, chest etc?
  3. Take cultures as clean as possible – aseptic approach – try and avoid those frustrating false positive BCs
  4. Contemplate changing the plan – look at the AB cover – is is sensible? Do you need to yank a line or call a surgeon to drain some pus?

Thanks Ben for the article.  Interns – relax, but do a more thorough job!    Casey


Add a Comment

Your email address will not be published. Required fields are marked *