… nitroglycerin isn't for chest pain. Nitroglycerin is for vasodilation.
It just so happens that coronary artery vasodilation often happens to relieve chest pain in patients with stable angina. In the genuine acute coronary syndromes, not so much.
I have to agree with Kaiser, and it's just this sort of unmitigated horse shit that gives me the pink leg* whenever I read it. "Administer 3 nitroglycerin and contact medical control" is one of the sillier rules that persist in modern EMS protocols, implemented by those absentee medical directors Rogue Medic likes to rail about so much. Folks, the 3 nitro rule doesn't apply to us.
It has never applied to us.
Three nitros was simply the trigger for the patient to call 911. It was something the cardiologists told their patients: "Here, put one of these little white pills under your tongue when your chest hurts. Take one every five minutes, and if you take three of them and your chest is still hurting, call 911."
That's all it was – a threshold for summoning the medical professionals to render further care. Yet in many EMS systems, it's also the set of protocol handcuffs that force those same medical professionals to limit their treatment to no more than what the patient can do himself.
The only legitimate endpoints for nitroglycerin administration are relief of symptoms, and hypotension.
And heck, even that's a matter of some debate. Some sources consider a BP of 100 systolic to be the endpoint, while others say it's 90 systolic. For my purposes, I'm not real concerned with a BP hovering between 90 and 100 systolic, unless they start out that way.
The folks that screech about an EMT-B assisting a patient with their prescribed nitroglycerin love to use the Right Ventricular Infarction Bogeyman to support their argument that no one but a paramedic with a 12 lead EKG machine should be fooling around with nitroglycerin, despite the fact that many of those same medics don't even bother to do the right-sided chest leads to diagnose that right ventricular infarction.
They also ignore the fact that an RVI patient who is preload dependent, usually looks that way. They have, like, clinical signs and stuff like orthostatic syncope or dizziness, Kussmaul's Sign, or the really big clue: they're borderline hypotensive to begin with. You're not gonna run into many of them that have a BP of 150/90 and then go into the toilet with one dose of nitro. More likely, they're gonna be hovering in the "Hmmm, I wonder if I oughta be giving nitro with a BP in that range," territory. If your paramedic spider sense is tingling that way, it doesn't necessarily mean don't give the nitro; it just means you should have a means of dealing with potential hypotension before it occurs. Get your line first.
For the most part, the problem with nitroglycerin isn't that we're giving too much of it, it's that we're not giving enough. Rather than futz around with Lasix on our acute pulmonary edema patients, filling their bladder when we ought to be emptying their lungs (because contrary to popular belief, most of these patients are not volume overloaded), we ought to be fogging the nitro to them like there's no tomorrow.
To hell with the 3 nitro rule, let's figure out a way to give nitro via in-line nebulizer attached to our CPAP masks.
And just in case I didn't make my point earlier, I'll repeat it: Nitro isn't for pain relief, it's for vasodilation.
If it relieves their pain, fine, there's no need for narcotics. But if it doesn't relieve their pain, you ought to be dispensing the opiate candy toute suite, with a goal of zero pain, while still maintaining an adequate respiratory rate and blood pressure. Less pain equals less catecholamines equals less myocardial workload equals smaller infarct size equals better outcomes.
But still keep giving the nitro anyway, because like I said before, nitro isn't for pain relief.
Nitro is for vasodilation.
* Pink leg is when the red ass has gotten so extensive that it has spread into the surrounding tissues.