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

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Is 50 NTG Too Much for One Patient?


Image credit. Three different forms of nitroglycerin, intravenous, sublingual spray, and the nitroglycerin patch.
 

In the comments to Unreasonable Fear of Hypotension and High-Dose NTG – Part I is the following from Kasey Marshall on the patient I treated with over 50 NTG (NiTroGlycerin – GTN GlycerylTriNitrate in Commonwealth countries) for CHF/ADHF (Congestive Heart Failure/Acute Decompensated Heart Failure).
 

My question is how long did the study go on that one patient received over 50 NTG tablets and is still functioning.

 

That patient was not in the study.

That was a patient I was treating with over 50 NTG.

The patient’s systolic blood pressure (the top number) never dropped below 200 mmHg.

Where is the problem?
 

I didn’t think that an individual was supposed to receive more than 3 NTG tablets in 5 minutes intervals before professional medical assistance.

 

As used in this case, NTG is an off-label use of NTG, but there is good evidence that high-dose NTG is safe and effective for CHF/ADHF. There is better evidence for high-dose NTG to improve outcomes for CHF/ADHF patients than there is evidence that standard-dose NTG improves outcomes for patients with chest pain/heart attacks/ischemia.
 

INDICATIONS AND USAGE
Nitroglycerin is indicated for the acute relief of an attack or prophylaxis of angina pectoris due to coronary artery disease.
[1]

 

I am a paramedic.

I am professional medical assistance.

One reason for the maximum of 3 NTG is to encourage the patient to go to the hospital and not stay home taking NTG, which wears off quickly. Once at the hospital, the patient will often be receiving IV (IntraVenous) NTG.
 

Patients with ischemic discomfort should receive up to 3 doses of sublingual or aerosol nitroglycerin at 3- to 5-minute intervals until pain is relieved or low blood pressure limits its use (Class I, LOE B).[2]

 

By ischemic discomfort, they mean heart attack symptoms, not CHF patients, but they do not provide any evidence. They suggest that there is evidence by writing (Class I, LOE B), but there is not a single reference listed to support this.

There is no reference to doses for CHF treatment. Doses for CHF should be much higher than doses for heart attack.
 

I know the earlier NTG is administered, the better but I think that there should be a limit on how much can be can be administered to one patient in a 48 hour period before more serious medical attention should be sought.

 

I have not yet had a transport that came close to 48 hours, so I do not worry about that kind of time period.

Serious medical attention? Rein in my pathetic attempts at humor? 😳

We should give NTG to CHF patients until it is coming out of the patient’s ears, until the patient’s systolic blood pressure drops by 30%, or until the patient improves.

We should be giving IV boluses of 1 mg or 2 mg every three minutes with CPAP (Continuous Positive Airway Pressure), rather than interrupting CPAP to give SL (SubLingual) NTG or using NTG by an ineffective route (paste that is not absorbed through the skin, because circulation is shunted away from the skin).
 

Conclusion: In this single-center, retrospective, unadjusted analysis of primarily African-American patients with acute hypertensive heart failure, nitroglycerin administered by higher dose bolus without concurrent intravenous infusion was associated with a significant decrease in ICU admissions and hospital length of stay. Based on our findings, bolus higher dose nitroglycerin appears to be a viable option for the management of such patients.[3]

 

The IV bolus NTG was better than the IV drip NTG.
 

I know when my mom had a prescription for NTG she was only told to take two, NTG tablets and if a third was needed to call paramedics. And that it was needed two days in a row that she needed to stay in the hospital for observation.

 

I expect that the reason for staying in the hospital was the heart condition that resulted in her taking the NTG.

Two doses of NTG will wear off quickly and are not a reason for hospitalization.

EMS will probably be giving multiple-dose NTG every 3-5 minutes, often 10, 20, or 30 NTG to one patient for CHF/ADHF.
 

Administration of high-dose nitroglycerin is an effective treatment that has been shown to improve the respiratory symptoms associated with ADHF, and decrease the incidence of death due to myocardial infarction and mechanical ventilation, particularly when initiated early.4 – 6 [4]

 

MSN (Multiple Simultaneous Nitroglycerin) is safe and effective for CHF/ADHF.
 

CONCLUSION:
Hypotension was rare and self-limited in prehospital patients receiving MSN.
[4]

 

The scary side effect of high-dose NTG almost never happened, but when hypotension did occur, it went away without any need for treatment.

Footnotes:

[1] INDICATIONS AND USAGE
NITROGLYCERIN tablet
[Glenmark Generics Inc., USA]
DailyMed
FDA Label

[2] Nitroglycerin (or Glyceryl Trinitrate)
2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science
Part 10: Acute Coronary Syndromes
Initial General Therapy for ACS
Free Full Text from Circulation.

[3] Nitroglycerin for Treatment of Acute, Hypertensive Heart Failure: Bolus, Drip or Both?
Kwiatkowski GM, Saely S, Purakal J, Mahajan A, Levy PD/Detroit Receiving Hospital, Detroit, MI; Wayne State University School of Medicine, Detroit, MI
Annals of Emergency Medicine, Volume 60, issue 4 (October, 2012), p. S9.
ISSN: 0196-0644 DOI: 10.1016/j.annemergmed.2012.06.049
Abstract 22 Indexed with OhioLINK Journal Article Locator

[4] Prehospital High-dose Sublingual Nitroglycerin Rarely Causes Hypotension.
Clemency BM, Thompson JJ, Tundo GN, Lindstrom HA.
Prehosp Disaster Med. 2013 Aug 21:1-4. [Epub ahead of print]
PMID: 23962769 [PubMed – as supplied by publisher]

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Comments

  1. So, my comment isn’t directly related (or even indirectly related…) to this post, but here goes anyway, since I spent the past weekend thinking about this blog and what I’ve gleaned from it over the years:

    I sat through an EMT refresher this weekend that also included the national EMT-B to EMT transition material. I noticed a few things that are *finally* catching on (and even better, this was a class of mostly volunteer EMTs from rural areas, so it’s making its way down).

    The quote “let’s apply some common sense to it” was used in the context of Mechanism of Injury, and actually critically thinking about MOI in relation to the situation and what the patient actually might need, instead of just taking action for the sake of MOI.

    Even better, the instructor at one point said, “I know we’re moving away from boards and collars, and there’s REALLY really good reason for that…”

    Instantly I thought of the myriad studies and articles I’ve read thanks to this blog. Well…hopefully medical direction soon follows what people are now actually saying…

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