Nitro & hiccups/indigestion?

[korvus]

I had a quick question that I couldn't find the answer to online. I was looking at our protocols today and noticed that the chest pain protocol said nitro was contraindicated with "Epigastric distress or hiccups accompanying symptoms of acute myocardial infarction". My net search found this which seemed to agree:

http://books.google.com/books?id=f3ePQZDXpwwC&lpg=PT410&ots=E1Fj-bu045&pg=PT410#v=onepage&f=false

Do not give nitroglycerin if there is hypotension or bradycardia, and do not give it to patients having epigastric symptoms (“indigestion”) or hiccups.

So I have some evidence that it is a "real" contraindication (instead of some wacky theory our medical director came up with). What I can't find is WHY, and it always drives me crazy when I hear something like that and can't figure out why. If I learn why, I'll remember forever, but if I don't, I'll probably forget this tomorrow. :huh:

Anyone happen to know why you wouldn't want to give nitro to someone with hiccups/indigestion? Thanks!

 

[JB42]

I am also having trouble finding an answer to this. Google has failed me. :sad:

Anyone have any insight?

 

[WolfmanHarris]

Interesting. Not a contraindication in our medical directives.

My best guess on this would be that the stimulation of the vagus nerve that can be caused by hiccups could potentially create bradycardia and that in general their BP and HR may be unreliable running the risk of them falling outside a safe range for NTG administration.

 

[JB42]

My best guess on this would be that the stimulation of the vagus nerve that can be caused by hiccups could potentially create bradycardia and that in general their BP and HR may be unreliable running the risk of them falling outside a safe range for NTG administration.

Only thing I could think of as well, was some type of vagal stimulation, but what about just general indigestion then?

 

[WolfmanHarris]

Only thing I could think of as well, was some type of vagal stimulation, but what about just general indigestion then?

No clue. Our indication/contras for NTG are:
- A&O (unless tx acute cardiogenic pulmonary edema)
- BP greater than 100mmHg systolic
- HR <160 and >60 bpm
- Hx of NTG use unless iv initiated
- no sildenafil (ED meds or revatio) within 48 hours

 

[ResTech]

It sounds to me like a poorly worded protocol. Sounds like the medical director doesn't want overzealous administration of nitro.

However, many cardiac patients present with epigastric symptoms... weird. I don't think there is any physiological reasoning for ir. I think its worded that way more so for indication.

It's my understanding that the actual cause of hiccups is unknown or poorly understood but is agreed that they are spasms of the diaphragm which is mainly innervated by the phrenic nerve. Does the vagus nerve also innervate the diaphragm?

 

[JB42]

I only thought vagal nerve stimulation from the actual physical mechanism. Not how they are stimulated. It was just a far reaching grab at something with no real evidence.

There is no mention of this in the NH protocols either. Maybe it really is an attempt to stop unnecessary administration of nitro in patients who may have chest pain simply from indigestion or hiccups.

We have, at the top of our ACS protocol, this statement. "All patients with complaints of chest pain should not automatically be treated with ASA and NTG. Consider the likelihood of ACS based on the nature of the symptoms, the patient's age, cardiac risk factors, past medical hisotry, etc." Which is an attempt at the same thing, stopping unnecessary administration of nitro.

 

[korvus]

Thanks for all the replies. I would assume this is some odd quirk of our protocols (to be clear, these are for an industrial EMT unit, so they probably aren't as clear as you'd expect in a more professional unit that goes on more calls), but it seems to be mentioned in that textbook. That said, I wouldn't be surprised if our protocol came straight from that textbook -- I have reason to believe an EMT-I wrote the protocols and just ran them by the medical director for review and signature.

I can understand the desire to avoid giving NTG in inappropriate cases, and maybe that was the intent. Of course, if anyone comes up with a better answer, I'd love to hear it!

 

[rescue99]

Thanks for all the replies. I would assume this is some odd quirk of our protocols (to be clear, these are for an industrial EMT unit, so they probably aren't as clear as you'd expect in a more professional unit that goes on more calls), but it seems to be mentioned in that textbook. That said, I wouldn't be surprised if our protocol came straight from that textbook -- I have reason to believe an EMT-I wrote the protocols and just ran them by the medical director for review and signature.

I can understand the desire to avoid giving NTG in inappropriate cases, and maybe that was the intent. Of course, if anyone comes up with a better answer, I'd love to hear it!

Dissecting aortic aneurysm.

 

[46Young]

Dissecting aortic aneurysm.

That's why a good pt assessment and R/O of differentials prior to pharmacological therapy is of prime importance, not "see A, do B", following the cookbook.

 

[rescue99]

That's why a good pt assessment and R/O of differentials prior to pharmacological therapy is of prime importance, not "see A, do B", following the cookbook.

Don't forget diaphragmatic hernias