Friday, April 18, 2014

Pre-Hospital Furosemide – No, No, Also No

In Ottawa, pre-hospital care includes paramedics authorized to treat acute cardiogenic pulmonary edema in the setting of respiratory distress.  Their treatment, sensibly, includes nitroglycerin.  It also, insensibly, includes furosemide.

Decompensated heart failure, resulting in pulmonary edema and dyspnea, is indeed a sort of fluid overload.  However, these patients frequently are not hypervolemic – they may be euvolemic or even hypovolemic, with other underlying etiologies for decompensation than fluid retention.  This pushes the concept of a strategy for the treatment of acute cardiogenic pulmonary edema with furosemide even further down the nonsense pathway.  Yet, there it is.

This study, a retrospective review of presentations with pre-hospital furosemide administration and hospital diagnoses of acute decompensated heart failure, demonstrates essentially nothing.  The primary outcome was designed to detect serious adverse outcomes associated with furosemide administration, but their comparison groups – furosemide given to heart failure, furosemide given to misdiagnosed heart failure, and furosemide not given to heart failure – are clinically heterogeneous and require probably meaningless adjusted comparisons.  The authors find no significant difference, but this is simply a matter of sample size and study design – a treatment given to a group with no chance of benefit obviously suffers only harms.

Most damning, however, is the utter failure of pre-hospital providers to correctly diagnose heart failure.  Of the 272 cases of heart failure diagnosed on arrival to the ED, pre-hospital providers made the diagnosis in only 110 instances.  Then, pre-hospital providers incorrectly diagnosed an additional 58 cases with heart failure and administered furosemide – when the patient was diagnosed with pneumonia, COPD, or another alternative.

Just say no.

“Prehospital use of furosemide for the treatment of heart failure”

12 comments:

  1. You'll be happy to know, most areas removed furosemide about 5 years ago for all but third line in prolonged transports. Morphine was removed as well for acute CHF. Higher doses of NTG and CPAP are the only two real treatments used.

    Unfortunately, like everything in EMS, just because some areas are doing it right there will be many doing it wrong.

    I've just noticed this was a recent study, which seems odd as the studies our systems used were from the early 2000's!

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  2. More than 20 years ago (http://www.ncbi.nlm.nih.gov/pubmed/1590605), Rich Wuerz (RIP) showed that inappropriate prehospital use of furosemide led to increased in-hospital mortality. This study shows "Maybe not."

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    1. This link is dead, do you have more details about the study? Perhaps title and date, or DOI number?

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  3. Yes – this is quite the surprising study, to say the least. We have a long way to go in improving knowledge translation.

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  4. As others have stated furosemide had just about disappeared from pre-hospital based on a series of EBM. While this article once again states the obvious "often difficult to differentiate CHF/APE from other respiratory compromising situations, this article might not be the best to "tout" in as much as it concludes that even though 1/3 patients did not have CHF/APE there were no significant adverse outcomes. Unfortunately we have all too many cook book pre-hospital providers who follow the mantra of "why not try it ??"

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  5. Ryan -

    We've seen a somewhat similar rate of CHF misdiagnosis by EMS in other studies (e.g. http://www.ncbi.nlm.nih.gov/pubmed/23484502), but perhaps we should be a little bit more generous with the results. In these studies (also including http://www.ncbi.nlm.nih.gov/pubmed/10155436), medic accuracy was compared with ED physician diagnosis, which seems a bit unfair. Given the longer time course in the ED, as well as the larger array of diagnostic options, it doesn't seem as though we have a clear picture of medics' diagnostic abilities.

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    1. I certainly don't blame the medics for misdiagnosis – even the ED gets these patients wrong. And, plenty of ED docs will still empirically make the same mistake of giving furosemide in settings of diagnostic uncertainty. Regardless, it makes zero sense to even place a treatment in the hands of paramedics if an accurate diagnosis is extraordinarily difficulty.

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    2. Oh, very much agree with the larger point!

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  6. Yup. In almost all cases it's not a volume problem, it's a distribution problem - which is obvious, if you actually think about the usual mechanism behind it.

    Our regional protocols do still allow furosemide, but it's very timid ("may be effective in selected patients") and requires first consulting with medical control. Personally, I doubt I would ever actually ask.

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  7. My medical director refuses to take it out of the CHF protocol, he says he has seen it work. None of the Paramedics in my service give it and we generally "forget" to use it or run out of time and just didnt get to it because we were busy trying to get the CPAP and nitro going

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  8. How about, for starters, banning the phase, "That's audible rales!" from across the room?

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  9. In Sweden furosemide is given as some kind of wonder drug for dyspnea. I have seen lots of patients with sepsis given furosemide by EMS because they heard rales on auscultation, even though they did acknowledge the underlying sepsis.
    Unfortunately the doctors aren't doing much better. COPD patients are often given furosemide by the internists, since there might be a little CHF contributing to the dyspnea, especially if the NT-proBNP is slightly elevated.

    Nice post, but I shouldn't have read it this late. Now I'm too upset to fall asleep.

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