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

- Rogue Medic

EMS NTG for CHF – Bolus or Infusion – Part I

In response to A Comment on Saving Patients from Low Doses of NTG, there is the following comment from Too Old To Work, Too Young To Retire.

Intubation, with or without RSI is far riskier for the patient. Not to mention that it lengthens ICU stays, has the risk of VAP, and lastly drives up costs. It’s the VAP that’s the killer, sometime literally.

Abbreviations used are listed in the footnotes.[1]

This is the most important difference between intubation (Invasive Positive Pressure Ventilation) and CPAP (NIPPV = Non-Invasive Positive Ventilation). Invasive airways lead to pneumonia.

The attributable morbidity and mortality of VAP are clinically important. In a prospective, matched cohort study, patients with VAP remained in the ICU 4.3 days (95% CI, 1.5 to 7.0 days) longer than patients who did not have VAP and had a trend toward an increased risk for death (absolute risk increase, 5.8% [CI, 2.4% to 14.0%]) (14). Six other studies using a matching strategy found a prolonged length of ICU stay associated with VAP (range, 5 to 13 days) and attributable mortality ranging from an absolute risk increase of 0% to 50% (15–20).[2]

Longer ICU stays and increased risk of death with intubation. What if they looked exclusively at patients intubated by EMS? How much longer would the ICU stays be? How much higher would the risk of death be?

Avoiding intubation is important.

CPAP helps to avoid intubation.

High dose NTG helps to avoid intubation.

Furosemide (Lasix) does not.

What should we use? CPAP and high-dose NTG.

What should we avoid? Intubation and Lasix.

We don’t see intubation in the hospitals for CHF patients very frequently. In fact, they were ahead of us on using CPAP by several years. That angered a lot of the medics because we knew that there was a better way to treat patients.

We still do not use treatment that is aggressive enough.

This is just one of the ways that people kill patients with – You can’t be too careful.

We have been too carefully killing patients.

I’d love to be able to do IV NTG in the field, but can’t seem to get our medical director interested in it. That might be because someone else has to approve the purchase of the pumps. It sure would help patients, though.

Here are some comments from someone concerned about the use of IV NTG by EMS without pumps –

It is generally agreed in the literature that for intravenous administration, the initial dosage should be set to 5 mg/min and this dose increased by 5 mg/min every 5 minutes until the desired effect is achieved or systolic blood pressure decreases below 100 mm Hg or a dose of 200 mg/min is attained.2[3]

This dose is not just too low, but this dose is so low that it will kill patients.

The median time of application was 12 minutes (range 4 to 33 minutes), and median applied nitroglycerin dose was 68 mg/min (range 35 to 255 mg/min). We concluded that nitroglycerin was excessively overdosed in regard to time of therapy.[3]

These doses are probably still too low.

Presumably severe clinical consequences were prevented only by the relatively short ambulance time in an urban setting.[3]

Here is one problem with this comment – there is no reference to any adverse effect from the higher than usual doses of NTG.

Why?

Because these doctors have probably been killing patients by not giving hypertensive CHF patients enough NTG.

If the NTG were dangerous, they would have seen adverse events in patients receiving NTG for periods much longer than the effect of NTG. NTG wears off very quickly, so 10 minutes or 20 minutes would be plenty long enough to kill patients, but these NTG doses were not excessive, even though these doses scared the doctors.

Too much fear.

Plus

Not enough understanding of medicine.

Equals

Dead patients from inadequate doses of NTG.

To be completed in Part II.

Footnotes:

[1] Abbreviations
RSI = Rapid Sequence Induction/Intubation
VAP = Ventilator-Associated Pneumonia
CPAP = Continuous Positive Airway Pressure
NIPPV = Non-Invasive Positive Ventilation
NTG = NiTroGlycerin (in Commonwealth countries, GTN + GlycerylTriNitrate)
IV = IntraVenous
SL = SubLingual

[2] Evidence-based clinical practice guideline for the prevention of ventilator-associated pneumonia.
Dodek P, Keenan S, Cook D, Heyland D, Jacka M, Hand L, Muscedere J, Foster D, Mehta N, Hall R, Brun-Buisson C; Canadian Critical Care Trials Group; Canadian Critical Care Society.
Ann Intern Med. 2004 Aug 17;141(4):305-13.
PMID: 15313747 [PubMed – indexed for MEDLINE]

Free Full Text from Annals of Internal Medicine

[3] Preclinical intravenous nitroglycerin therapy.
Roeggla G, Hauser I, Wagner A, Roeggla M.
Ann Emerg Med. 1998 Mar;31(3):416. No abstract available.
PMID: 9506507 [PubMed – indexed for MEDLINE]

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Comments

  1. In our system, we’re told to use buckets and buckets of nitrates, and PEEP vavles. (We do not have CPAP)

    Seems to work.

    First time I saw a patient like this I was shocked at how much NTG (GTN in our language) my paramedic buddy was squirting in/… but it works.

  2. The previous system I worked in carried NTG infusions, it was rare my CHF patients didn’t get a 1.2mg SL “loading dose” and end up on at least 75mcg/min, yet in two years I never bottomed anyone out. Nor did I have to intubate any CHF’ers when combined with NIPPV.

    The clinical department and medical director knew what I was doing and approved, even though it went against “protocol”. Other paramedics however, looked at me like I had three heads.