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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Dave,

Have you been a medic long enough to remember when we could save lives when the electricity was off? :-)

Ben
Ben, like usual I agree 100% with this comment! I have worked with medics reach for the atropine and have spoken with new medics that have pushed atropine with a hour of 59! Why did they, because protocal said below 60 they could! In my state the protocal for d50 was under 100!! I recall in school we had been taught that 70 to 110 was considered normal! To many medics are treating the monitor and not the pt!!
No I didn't. Is this to cut down on prehospital patient stress?

Or, "if we can't fix 'em we can at least make them enjoy the ride."
Joe,

You can check out the Duke research at the links I posted earlier in this thread.

Brief and incomplete synopsis: The Duke research shows that each hemeglobin molecule carries four oxygen molecules when it's fully saturated. However, three of each four oxygen molecules typically don't unload in the capillaries, so only 25% of the circulating oxygen actually participates in cellular respiration. Nitric Oxide inhalation helps the hemeglobin shed additional oxygen molecules in the capillaries, which aids cellular respiration.

The preliminary conclusions of the research are that maybe we should be giving hypoxic patients Nitric Oxide instead of Oxygen.

Ben
Joe,

The study refers to Nitric Oxide. I believe the "enjoy the ride" you spoke of refers to Nitrous Oxide, which is a different medical gas.

Ben
Shoot! I was SO looking forward to being able to dispense that gas, too... might have prolonged my stay in the back of the bus.

Thanks for pointing that out Ben. D'oh! My bad. Need new glasses.
Capnography doesn't measure ANY oxygen at all - it measures blown-off carbon dioxide. Capnography is a measure of respiratory status, but it is not a measure of how well oxygen is perfusing anywhere outside the lungs.

From The Free Medical Dictionary: "capnography" "The measurement and graphic display of CO2 levels in the airways, which can be performed by infrared spectroscopy; capnography facilitates Pt management by providing
1. Continuous and noninvasive monitoring of ventilation in critically ill Pts and 2. Early detection of clinically significant changes in respiratory status by displaying changes in the amount of CO2 and abnormal CO2 waveform
"

Notice the glaring absence of any mention of oxygenation in the capnography definition. If you want to measure oxygenation, you can do it a little slowly with Pulse Ox or not at all with capnography.

The "litmus paper" to which you refer isn't actually litmus paper. Litmus paper is one of several colorimetric technologies including the Drager and MSA hazmat sampling tubes, pH paper, oxidizer paper, and the purple/yellow ETCO2 detectors. They're not digital, and they're qualitative-not-quantitative, but they are indeed a form of ETCO2 monitoring. The colorimetric ETCO2 monitors are cheap, but they're unreliable for long downtime CPR patients, in high heat/humidity environments, and have several other pitfalls.

I'm not knocking digital waveform ETCO2, but it is expensive and it's a new technology, especially the versions for non-intubated patients. Cost to upgrade a single LifePak 12 from non-ETCO2 to ETCO2 monitor capability - approximately $5,000 per monitor, plus the cost of the single-use capnography tube links.

The bottom line is that capnography is an emerging technology, while pulse oximetry is a proven technology. As has already been pointed out, stand-alone pulse oximeters are so inexpensive that individual EMT-B's sometimes purchase their own. I don't see that happening with digital waveform ETCO2.

As for "Pulse ox only measures the percentage of red blood cells that are carrying "something" anything."...that "something/anything" is going to be oxygen and nothing but oxygen unless the patient has experienced one of the following hazmat inhalations:

Carbon monoxide - carboxyhemeglobin replaces oxyhemeglobin
Cyanide - cyanohemeglobin replaces oxyhemeglobin
Nitrate/Nitrite - methemeglobin replaces oxyhemeglobin

Most EMTs and paramedics are smart enough to figure out the difference between a CHF call at a nursing home, a pediatric asthma attack, an AMI chest pain patient, and a hazmat inhalation patient without the pulse ox. The anti-pulse ox arguements ignore an essential rule of medicine..."When you hear hoofbeats, look for a horse, not a zebra." The pulse ox is going to see the horse (oxygen) virtually every time. The zebras are generally obvious long before you get a pulse ox on the patient. If you have one of those hazmat inhalations, that's an appropriate time to keep the pulse ox in the bag and just deliver high-flow oxygen. If the patient is an AMI chest pain patient, the pulse ox is generally a reliable indicator of how well your oxygen therapy is doing at getting oxygen volumes delivered to the cells.

If your service can afford it and you want to be able to discriminate between oxyhemeglobin and the big 3 mimics, get a RAD 57. RAD 57 is a pulse oximeter that has additional sensors that discriminate between oxyhemeglobin and the above three toxins. My department has one of these. It's been helpful to rule CO inhalation in or out from several house fire patients and as a firefighter rehab protective mechanism.

Once again, I'm not anti-capnography, but it has plenty of limitations and pitfalls, just like every other tool in the toolbox. Pulse ox is a lot cheaper, it's more readily available, and has a proven field history. There are very few EMS systems using capnography, and most of the ones that do use it only to confirm tracheal intubation.

Ben
I learned in EMT-Basic class that there are times when you can give pts too much oxygen. If you hyperoxygenate the pt in arrest, it will cause the intrathoracic pressure to go up which will decrease the blood flow returning to the heart.


I think.
You did the right thing. although getting a room air sat would have been good as far the medic its to late to get a room air sat if the pt has already been on O2. Our MD tells us that if they have COPD still go ahead with NRB at 15 and knock out their hypoxic drive and tube them that way they dont have to breath on their on and we can breath for them that is a lot less stress on the pt. They will take care of their breathing in the ED.
Edward, Your MD is ignoring the evidence that intubation is assiciated with dramatically increased morbidity and mortality for COPD patients. Once COPD patients lose their hypoxic drive, it is very difficult to wean them from the ventilator as well. In addition to being bad for the patient's long-term health, intubation increases ICU stays and healthcare costs.

If the COPD patient can reach oxygen saturation in the 90%-plus range on 2 or 3 liters, there's no reason to give them higher oxygen concentrations. If they need ventilatory support, CPAP is much better than intubation, and it can be done with lower oxygen concentrations and without knocking out the only thing that is keeping the patient breathing. It can do it without saving them from the acute problem just to help kill them with a chronic problem, too.
I relate chest pain to blowing a going fire. Would you use a preconnect or would you pull a blitz line? I truly believe "Big fire Big water." If some is complaining of cardiac chest pain, this usually means that the heart is not getting enough O2 to a portion of the muscle. They need "Big Water" at this point. I would have done exactly what you did. Protocol calls for a NRB at 10Lpm where I practice. You can always go outside of protocol, but you should have a really good reason for doing so. And, I agree, you treat COPD patients a little differently, but unless you are transporting over a long distance for a long period, you usually aren't going to knock a COPDers hypoxic drive out. Now intubating a COPDer, totally different. There is a good chance that they may not make it off the vent. You can never go wrong by treating the patient and following local protocol.
High flow O2 has a multitude of uses, not the least being pain relief. Relieving the pain also relieves the stress thereby allowing for better perfusion, in this case cardiac. Better perfused tissue is healthier than poorly perfused tissue, therefore high flow O2 is proper treatment. That said, I understand that high flow O2 is contraindicated in COPD pts BUT was taught that in the field to give high flow O2 and be prepared to bag. This came from a Respiratory Therapist/EMTI, who demonstrated many times that this is quite effective and that in the pre hospital setting, unless you have extensive transport times, the pt usually does NOT experience respiratory arrest and the O2 has done more good than harm.
Pulse Ox is an effective tool in determining O2 sat BUT we must always treat the patient NOT the machinery. Also, find out what is normal for the pt, sometimes their "normal" is abnormal. We also need to remember that pts are human beings and sometimes a little comfort is just as effective as conventional medicine. Pre Hospital medicine requires a whole body approach. There have been several times that as an EMT-B I was unable to get an ALS intercept and had to use breathing techniques, stress reduction and O2 to alleviate pain, anxiety, aggitation and other sx.
Fortunately in this situation the pt did not seem to suffer any detrimental effects from the change in O2 delivery systems but the best thing to do is document....."If is isn't written down, you didn't do it" is the best rule to live by!
Of course, once the pt is turned over to a "higher qualified" caregiver, than you are absolved from anything that happens as a result of them changing your treatment.

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