I was on a call the other day, 50s male with chest pain, cardiac history, pain 8/10, etc. Pulse about 80. NYS BLS protocol states that high flow oxygen should be given via non-rebreather mask. This has been the protocol for the past 20 years at least, and is also considered routine medical care for all levels in our area.

ALS arrives on scene while I prepare the NRB. The ALS tech says "No, put him on 4 lpm with a cannula." I considered that a moment, then said "Nope, I'm giving him 15 per protocol."

Two or three minutes later, the patient reported vast relief from pain with the NRB. Having transferred care over to another crew, I watched as the ALS tech removed the NRB so as to get a room air sat level.

Apparently, there is some belief that indicates that too much oxygen can constrict the cardiac vessels and complicate the situation. However, a "belief" is overruled by protocol, in my book.

Any thoughts or data on this?

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Pulse ox is inexpensive - http://www.semedicalsupply.com/pulse_oximeters.htm
It is a valuable tool to check oxygenation, regardless of the level of care to which the crew is certified.

If you do airway care or give oxygen, you should be using pulse ox as a diagnostic and therapeutic measuring tool. It's not the end-all, be-all, but it is another tool in the tool box.


I did a pretty extensive search today, and here's a synopsis of what I found.

Pulse oximetry is less than optimally reliable under the following circumstances:

1) Carbon monoxide, nitrate/nitrite, and cyanide inhalation poisonings. RAD 57 makes a pulse oximeter that can read the above chemical interferents and let you know if the saturation you're reading is all oxygen or an interferent from an inhalation poisoning.

2) Patients with compromised peripheral circulation - patients that are hypothermic, profoundly hypotensive, or who have peripheral vascular disease may not give accurate readings. However, these readings are typically lower than the core circulation oxygen values, so if you're reading high pulse ox values on a peripherally-compromised patient, you still can't have a patient with 101% oxygen saturation.

3) Patients that move a lot. This is typically transient, unless the patient is combative or seizing.
Interventions like IV benzodiazapenes (seizures, combativeness) or RSI (head trauma) will eliminate this problem.

4) Patients who have less than 70% saturation. These patients are in severe distress. If you get a "low" reading on a pulse ox, aggressively manage the airway, give high-flow oxygen, and aggressively manage other field-treatable problems such as hypothermia (rewarm and handle gently) or bradycardia (atropine, pacing).

There are new technology pulse oximeters (esophageal monitors that eliminate the periperal low flow problem (esophageal sensors) and that tell the operator if a low sat is a patient movement problem (wave form monitors).

There is no study I found that states that pulse oximeters are unreliable outside of one of the four parameters discussed above. Since the vast majority of patients who recieve oxygen don't fall into one of the above four categories, that indicates that pulse oximetry is still an effective patient monitoring tool in most situations.

Having more time to relax these days, I did another review of our state and regional protocols. Nowhere does it state that we should or should not use a pulse oximeter.

The ALS folks (EMT-Critical Care and EMT-Paramedic) carry pulse oximeters with them and do use these as part of their evaluation. I would assume that they have been trained in the cautions that Ben has outlined elsewhere.

I guess what I am driving at, is that a pulse ox is to us, a tool that we really should be trained on before we use it. I've not seen or heard of such training in our BLS curricula.

Thanks for the link - last time I checked (several years back) the prices were much, much higher and the vendors were few.
Here's some research on capnography. It seems that indications for capnography on non-intubated patients are few and far between...


There are some new ETCO2 monitors that work with nasal cannulas or non-rebreather masks, but they are not in common use yet and the monitors that work with them tend to be mucho expensive.

I would have to disagree with ya here.....Pulse ox only measures the percentage of red blood cells that are carrying "something" anything........ETCO2 has waay more information when used with capnography.....it responds immediately to any change in patient condition.....each exhalation is a new reading....pulse ox is very slow to respond......we have used pulse ox and the ETCO2 with capnography for quite some time here in our als system and have found that ETCO2 with capnography to be a much better tool and much more reliable.

I am however unfamiliar with what you mean by colorimetric technology, unless you are referring to the litmus paper in the BVM's and such....those SUCK.!!! and are worthless......that i do agree on. The ETCO2 and Capnography I am referring to is a digital ETCO2 reading and visual waveform capnography....we have the ability to utilize this tool on any patient........via cannula, bvm, ett, or whatever.....its a great tool!

Hope this helps clear my previous comment up a little...
For those still interested in this topic:

Tonight I happened to mention this call to our EMS Captain. She told me that this call was reviewed by our Medical Director, including my insistence on the NRB. The MD absolutely supported my position and treatment. I believe the ALS tech got spoken to as a result.

Did the ALS tech have pulse oximetry date to support his/her position? Without it, I'd vote for the NRB.
If pulse ox indicated a sat in the high 90's on room air, his/her position is a little more solid.

You might think about some inexpensive pulse ox technology on your BLS units, with Medical Director buy-in on the front end, if you can get it. That makes clinical decisions more evidence-based and less "Follow the cookbook, no matter what."

Unknown about any pulse ox data, Ben. On this particular call there was no pulse oximetry done by the tech prior to the request for a N/C.

That qualifies as a faux pas by the ALS provider, then.
Did you look up the Duke University research that says we should be giving patients inhaled Nitric Oxide rather than oxygen?

True Jenna!! Not every pt requires IV O2 and monitor either, but it seems that we are getting away from the ABC'S and doing IV O2 Ekg on all pt's. There is a small city that year end totals produced 90% als!! thats right 90%!! unheard of if you ask me. Todays medics are being taught the skills, but very little time is being spent on when to use the skills, it's ashame what my state and the medical directors are doing.
And i have "Reamed" cook book medics for poor exam skills!! I have noticed a great decline over the last 8 years in medics coming out of school. Seems the more schools that pop up the less quality of Medic. When i went to medic school 14 years ago we had hrs upon hrs of resp lecture, today these little schools cover that subject in 3 hours. The education just is not there like it used to be, and the pt suffers. I guess thats why we have EMS systems doing 90% ALS. Dont know whats going on....IV o2 ekg covers you on everything!! How sad has EMS become??
Actually, protocols can be tossed out the window on every call, if you wish to do so.
All you have to do is call and get an online medical control order for whatever you want to do.
If you can get the order for it, the online medical control orders trump protocols every time.

Interestingly, I've recieved commendations for saving lives while directly violating protocols.
Protocols simply do ont cover everything that can go wrong with the human body.

In some places, protocols are specifically cited as "guidelines".

Also, following protocols will NOT keep you out of litigation. Anyone can sue anyone else at any time, for anything, everything, or nothing. And...if you follow a cookbook protocol whose recipe doesn't exactly fit the patient you're treating, when you become the defendant, the plaintiff's attorney can use your protocols as evidence that you didn't use good clinical judgement in some circumstances.

Protocols should be used as an adjunct o good clinical decision-making, not instead of it.


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