Without evidence of benefit, an intervention should not be presumed to be beneficial or safe.

- Rogue Medic

The Return of the Irrational Maximum of 3 NTG

There is more to dislike about the 2010 AHA Guidelines. There are some improvements, but there is also the occasional return to the Dark Ages changes.

EMS providers should administer up to 3 nitroglycerin doses (tablets or spray) at intervals of 3 to 5 minutes.[1]

Are the authors of this experiencing stroke-like symptoms? Excited delirium? Mass hallucination? Did somebody slip some LSD into their drinking water?

What were they thinking?

We don’t know, because there is absolutely nothing in these new guidelines to support this sentence. No explanation at all.

What level of evidence was this based on?

Nothing is listed.

What is the reason for the change?

They do not explain.

Apparently, somebody had nostalgia for this old nonsensical limitation on the administration of NTG (NiTroGlycerin or GTN Glyceryl TriNitrate), so they put the baseless restriction back in the guidelines.

How many EMS systems will see this and decide that it is too risky to treat hypertensive CHF/APE/ADHF (Congestive Heart Failure/Acute Pulmonary Edema/Acute Decompensated Heart Failure) patients appropriately with the most effective medication we have?

We shouldn’t have a maximum of 3 NTG for even any single dose.

Triple doses are safe – even when repeated every 3 minutes.

As long as the patient is symptomatic and very hypertensive (180+ systolic pressure).

Quadruple doses are safe – even when given every 3 minutes.

As long as the patient is symptomatic and very hypertensive (180+ systolic pressure).

Quintuple doses are safe – even when given every 3 minutes.

As long as the patient is symptomatic and very hypertensive (180+ systolic pressure).

But if we follow the AHA Guidelines, we will not have the safe and efficacious treatment option of high-dose NTG.

This is one way to keep the number of EMS intubations high.

Footnotes:

[1] Prehospital Management – Initial EMS Care
Part 10: Acute Coronary Syndromes
2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care
Free Full Text Article with links to Free Full Text PDF download

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Comments

  1. Well this certainly goes to show just how little I know. That is our protocol RIGHT NOW. Although I see and know the benefits of increased doses, I really didn’t realize that there were systems treating that “aggressively”…seriously, I realy didn’t. I guess we really are backwoods after all.

    • We’re still 3 and call too, but we have somewhat restrictive medical direction. However, when we’ve called in the past for orders they have included high dose NTG.

      • Christopher,

        Some protocols do not even allow a medical command order to deviate from protocol, but I have been able to get orders from a lot of doctors before we had this change in protocol. I left one job over a disagreement about high-dose NTG.

        Try talking with the doctors about making this a standing order. Suggest that they compare the outcomes of the CHF patients receiving high-dose NTG and the outcomes of the CHF patients receiving a maximum of 3 NTG.

        It should not require a lot of patients to demonstrate the improved outcomes. It would take a lot to demonstrate the lack of harm, just because data on safety requires far more patients than data on benefit.

        Another way to convince doctors is to ask them –

        What doses do you use to treat these patients?

        How much more NTG do you give by infusion, than we give by tablet or spray, and you still do not have adverse events?

        • Yeah, myself and an FTO at my service have been pushing for lots of changes recently, however, something like the dosing schedule of NTG would require a state waiver. Not saying it isn’t worth the effort, Dr. Mears is pretty amenable to EBM changes to the protocols.

          • Christopher,

            There is nothing wrong with trying. Sometimes the doctors do not think that there is any interest from the medics in providing better care. When they realize that something is practical, the medical directors may be open to changes. The medical directors are there to provide the best care to the patients and improving patient care is exactly what you are suggesting.

    • FirstDueMedic,

      Well this certainly goes to show just how little I know. That is our protocol RIGHT NOW.

      What your protocol permits and what you know are not the same thing.

      Unfortunately, a lot of medical education has included this bit of mythology for decades.

      Although I see and know the benefits of increased doses, I really didn’t realize that there were systems treating that “aggressively”…seriously, I realy didn’t.

      The relevant portions of the CHF protocol for Pennsylvania follow. This is on standing orders. Even this is not aggressive enough, but it does demonstrate to plenty of doctors and medics the safety of NTG.

      SBP > 100mmHg1

      If not using Viagra-type drugs2,
      Nitroglycerin 0.4 mg SL
      (1-3 doses every 3-5 minutes3,4)

      3. After initial single tablet/spray of NTG, give nitroglycerin dose based upon blood pressure:
      a. 3 SL tablets or sprays – for SBP > 180
      b. 2 SL tablets or sprays – for SBP 140-180
      c. 1 SL tablet or spray – for SBP 100-140
      d. For patients on CPAP who do not tolerate SL NTG, may use 1 – 2 inches of topical nitroglycerin paste, if available.
      e. When available, may substitute nitroglycerin IV infusion 5 – 200 mcg / min titrated to SBP>100.
      4. NTG may be repeated every 3-5 minutes as long as blood pressure is greater than 100 systolic.
      [Note: One NTG repeated every 5 minutes is equivalent to a NTG infusion of 80 mcg/min]

      NTG infusion is optional, but 1 mg boluses of IV NTG would be a safe and practical alternative.

      I guess we really are backwoods after all.

      Not necessarily. You may have protocols that are more progressive in some areas. One of the things about EMS is that there is tremendous variation in the way protocols are written. Before we had statewide protocols, the county with the most progressive pain management protocols also had protocols that relied on Lasix for CHF.

      Here are some papers that you can pass on to your medical directors and to doctors at the hospitals you transport to. These are both review articles by some of the top doctors in CHF treatment.

      Prehospital therapy for acute congestive heart failure: state of the art.
      Mosesso VN Jr, Dunford J, Blackwell T, Griswell JK.
      Prehosp Emerg Care. 2003 Jan-Mar;7(1):13-23. Review.
      PMID: 12540139 [PubMed – indexed for MEDLINE]

      Free Full Text PDF

      Modern management of cardiogenic pulmonary edema.
      Mattu A, Martinez JP, Kelly BS.
      Emerg Med Clin North Am. 2005 Nov;23(4):1105-25. Review.
      PMID: 16199340 [PubMed – indexed for MEDLINE]

      Free Full Text PDF

  2. Our state EMS office must have a mole inside AHA, because this is exactly what they changed our protocols to over the summer. We went from no limit to max 3 q5, bowing to the idiots who think just because we have short transports every patient will be the same and never need anymore.

    Oh sure, we can give more, provided we have time to call and beg permission for it at the 15 minute mark.

    • CBEMT,

      Our state EMS office must have a mole inside AHA, because this is exactly what they changed our protocols to over the summer.

      Doctors do talk to each other. Somebody may have mentioned that this was seen as a good idea by some precautionary principle worshipers.

      We went from no limit to max 3 q5, bowing to the idiots who think just because we have short transports every patient will be the same and never need anymore.

      Why do medical directors restrict protocols without any evidence of harm?

      I don’t know, but I suspect that it is due to sub-therapeutic lorazepam levels in the medical directors.

      Oh sure, we can give more, provided we have time to call and beg permission for it at the 15 minute mark.

      Requirements for on line medical command permission demonstrate a lack of understanding of EMS and a lack of awareness of the way excellent EMS oversight is provided.

      What benefit is provided to the patient?

      Delay in care just so a doctor can feel that he/she is keeping the dangerous medics from being too dangerous?

      What level of dangerous is acceptable?

      The more a doctor relies on on line medical command permission, the greater the comfort level with dangerous paramedics.

      It would be better to remediate, or eliminate, the bad paramedics, rather than subject patients to dangerous medics.

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