NRB Flow Rate

[medichopeful]

Hi all,

I was reviewing PCRs for my colleges EMS unit, and I have a quick question. It may be a stupid one, but I figure I'll ask anyways.

I was reviewing a case where a student approached a member of our student security stating that he had had too much to drink. The student security officer called it into dispatch, and EMS was dispatched.

I wasn't on the call, so all I have to go by was what was on the report (which was seriously lacking, which is something that I'm going to work on improving in future training session). The patient stated that he was having difficulty breathing and numbness and tingling in his extremities, so he was placed on a NRB @ 5lpm (his SpO2 was 99%, respirations 12). Again, this is pretty much all I have to go on, besides that he was vomiting when EMS was on scene and had a BP of 118/76.

The big thing that stuck out to me when I was reviewing this was the oxygen therapy. In the textbook, it says that a flow rate of 12-15lpm is the correct flow rate for a NRB. Of course, this is the textbook and therefore not gospel, as lower flow rates and higher ones can be used as well. I'm not arguing that the flow rate should have been between 12-15 because "that's what the book says." I am, however, a little concerned about the flow rate that was used: 5lpm seems a little low.

I figured I'd ask here before I talked to the club about this, because I want to make sure that I'm not insane (at least, when it comes to this). Does anybody have any thoughts or comments?

Thanks!
Eric

 

[nakenyon]

Yes. The textbook says 12-15 lpm when using a NRB. As you said though, the textbook is not gospel. However the lowest I've ever seen a NRB used is 10 lpm. Not sure if you guys carry nasal canulas. Seems that might have made more sense in this situation. Just my .02. Not criticizing anyone. Just making a suggestion.

 

[medichopeful]

Yes. The textbook says 12-15 lpm when using a NRB. As you said though, the textbook is not gospel. However the lowest I've ever seen a NRB used is 10 lpm. Not sure if you guys carry nasal canulas. Seems that might have made more sense in this situation. Just my .02. Not criticizing anyone. Just making a suggestion.

Hey Junkie,
Yes we do carry NCs, and as far as I'm concerned if the flow rate is going to be that low then yes the NC would make more sense. It would seem that otherwise, there could either be a buildup of CO2 or a lack of O2.

 

[JPINFV]

10-15 is the magic number. However in my experience, and for multiple reasons, the seal between the face and the side of the mask is normally non-existant, which is going to limit the effectiveness of both the oxygen delivery (if you can't draw a suction, you won't draw oxygen from the reservoir bag) as well as the dangers of not using a proper flow rate. Essentially if the bag is not collapsing to any significant consent (a little is fine), then it's more of a treatment faux pas than anything else. Kinda of like recording odd number blood pressures.

 

[dmc2007]

I've always been taught 10-15. You are absolutely right in this regard. Did you maybe consider that the reporting individual meant to type 15 and merely left off the one?

 

[medicdan]

Here's the deal-- the reason the book says 10-12-15 is because an NRB has the capacity, if reservoir bag is empty, to asphyxiate a patient. The seal around the mouth and exhalation ports are never perfect, the opportunity still exist. If you are trying to be stingy, you could theoretically titrate the flow to respiratory rate and tidal volume, but that's a risky game, and not likely achievable at 5lpm. It was most likely a mistake on your corps member's part.

I have this endless rant about giving O2 to an intoxicated soul-- especially NRBs. I have more problem with the fact your EMT gave an NRB than the flow rate, simply because the patient was vomiting, and if poorly monitored, is much easier to asphyxiate them with vomit in the mask.
Why were they giving oxygen? Was it simply a textbook response for "AMS"?

What other causes can/could you rule out, even with no additional equipment? What additional history could you collect?

-- Rule out fall/head trauma with physical exam, history and friend's reports?
-- Rule out diabetic with physical exam (skin, etc), history? Any other medical history (Alert Tags?) AEIOUTIPS?
-- Rule out other drugs/meds (prescribed and non-prescribed) with history from patient, friends, scene, etc.
-- Does drinking history match level of consciousness/AMS? How many drinks? What kind? WHen did they start? end? When did they last eat? History of drinking? When did they last vomit? How many times (because AMS can increase after vomiting)?

What I'm encouraging you (and your members) is to examine other causes of AMS-- and not just provide textbook assessment and treatment. Think long and hard about the treatments you are giving (especially delivery method and dose of O2), and why you're really doing what your doing.

 

[abckidsmom]

It sounds like the patient was possibly hyperventilating, and I've heard of people putting low- or no-flow NRBs on people for hyperventilation, kind of for the breathe into the paper bag effect.

If QA is your job, I might follow up with the provider to see if that's what they meant to type. A typo for 15 seems equally likely.

 

[medichopeful]

Here's the deal-- the reason the book says 10-12-15 is because an NRB has the capacity, if reservoir bag is empty, to asphyxiate a patient. The seal around the mouth and exhalation ports are never perfect, the opportunity still exist. If you are trying to be stingy, you could theoretically titrate the flow to respiratory rate and tidal volume, but that's a risky game, and not likely achievable at 5lpm. It was most likely a mistake on your corps member's part.

I'm pretty sure it was a mistake/ bad treatment choice as well. I don't believe that it was a titrated flow for a variety of reasons, including the fact that there was absolutely no mention of titration (the report said that they put him on a NRB @ 5lpm, no mention of titration or anything of that sort.)

I have this endless rant about giving O2 to an intoxicated soul-- especially NRBs. I have more problem with the fact your EMT gave an NRB than the flow rate, simply because the patient was vomiting, and if poorly monitored, is much easier to asphyxiate them with vomit in the mask.

This is a very good point.

Why were they giving oxygen? Was it simply a textbook response for "AMS"?

From what the report says, it was in part because of the complaint numbness/tingling and shortness of breath. Unfortunately, the report is not that thorough, so I'm only going by what I have.

What other causes can/could you rule out, even with no additional equipment? What additional history could you collect?

-- Rule out fall/head trauma with physical exam, history and friend's reports?
-- Rule out diabetic with physical exam (skin, etc), history? Any other medical history (Alert Tags?) AEIOUTIPS?
-- Rule out other drugs/meds (prescribed and non-prescribed) with history from patient, friends, scene, etc.
-- Does drinking history match level of consciousness/AMS? How many drinks? What kind? WHen did they start? end? When did they last eat? History of drinking? When did they last vomit? How many times (because AMS can increase after vomiting)?

I didn't mention it originally, but the patient didn't have any known past medical history. Due to the fact that the report isn't very thorough (at all), I don't know what else was done.

What I'm encouraging you (and your members) is to examine other causes of AMS-- and not just provide textbook assessment and treatment. Think long and hard about the treatments you are giving (especially delivery method and dose of O2), and why you're really doing what your doing.

If the members in the unit would do this, that would be great. However, I don't see it happening very soon (for reasons I'll PM you).

Thanks Dan!

 

[Veneficus]

or if you put somebody on highflow o2 and it is more than they can tolerate you might be reducing the flow until they can.

People were not meant to breath 100% o2.

 

[medichopeful]

It sounds like the patient was possibly hyperventilating, and I've heard of people putting low- or no-flow NRBs on people for hyperventilation, kind of for the breathe into the paper bag effect.

If QA is your job, I might follow up with the provider to see if that's what they meant to type. A typo for 15 seems equally likely.

I'll talk to them when I get back to school after break, but I don't believe it's a typo (it was written in 2 different places by hand as "5 lpm."

If the patient was hyperventilating, this might have been acceptable (as it could cut down on respiratory alkalosis by increasing the amount of CO2 in the blood). However, the patient was placed on the 5lpm after his respirations were counted to be at 12 rpm, so I'm pretty sure it wasn't for that reason.

When I talk to them I'll ask about it though!
Eric

 

[medichopeful]

I've always been taught 10-15. You are absolutely right in this regard. Did you maybe consider that the reporting individual meant to type 15 and merely left off the one?

A typo is possible, but they would have had to do it twice (see post above).

 

[medichopeful]

or if you put somebody on highflow o2 and it is more than they can tolerate you might be reducing the flow until they can.

People were not meant to breath 100% o2.

I'll be following up with those on the call, but as I understand it they just put them straight on 5lpm

 

[Hockey]

Brown bag idea is dangerous just FYI

Asthma and heart attacks, can be confused with hyperventilation. In such cases reducing oxygen and increasing carbon dioxide can be deadly.

 

[medichopeful]

Brown bag idea is dangerous just FYI

Asthma and heart attacks, can be confused with hyperventilation. In such cases reducing oxygen and increasing carbon dioxide can be deadly.

Good to know Hockey. Thanks!

 

[usafmedic45]

The patient stated that he was having difficulty breathing and numbness and tingling in his extremities, so he was placed on a NRB @ 5lpm

Welcome to a good excuse to suspend the EMT responsible for that move. In fact, I've fired someone for that exact action before. If they are that stupid, they have no business ever touching a patient.

 

[EMSLaw]

I'll talk to them when I get back to school after break, but I don't believe it's a typo (it was written in 2 different places by hand as "5 lpm."

If the patient was hyperventilating, this might have been acceptable (as it could cut down on respiratory alkalosis by increasing the amount of CO2 in the blood). However, the patient was placed on the 5lpm after his respirations were counted to be at 12 rpm, so I'm pretty sure it wasn't for that reason.

When I talk to them I'll ask about it though!
Eric

Even if the patient were hyperventilating, putting them on a NRBM that's either not hooked up or is hooked up at a very low flow (the equivalent of a brown paper bag) is the sort of field expedient that can get you in a lot of trouble. I'm not saying I've never seen it done - heck, I've seen medics do it on numerous occasions - but it's a violation of the standard of care.

I would be more inclined to believe that the patient had numbness and tingling in his fingers because he's drunk. However, I didn't see or evaluate the patient, and ETOH tends to mask lots of possibly really bad stuff.

If the patient is on 5lpm, then a NC is the correct tool for the job.

 

[18G]

The standard is 10-15lpm with NRB as already stated. If you need to flow less than 10lpm then use a simple face mask or nasal cannula.

A report of dyspnea and numbness/tingling, SpO2:99% + ETOH = hyperventilation.

 

[usafmedic45]

A report of dyspnea and numbness/tingling, SpO2:99% + ETOH = hyperventilation.

....or hypercapnia (hypoventilation) can induce much the same sensation as hyperventilation (hyperventilation).

 

[medichopeful]

Update

So here's an update. I talked to the EMT involved, and he said that they did it as a sort of placebo effect because "he was not in apparent resp. distress but was breathing at a 'normal' rate."

I'm not really that informed about the legality of placebos in EMS (I'll be looking it up in a few), but does anybody have any thoughts on this? Could the low flow rate in the NRB cause an excess of inhaled CO2?

 

[usafmedic45]

Could the low flow rate in the NRB cause an excess of inhaled CO2?

Yes, along with hypoxia.

I'm not really that informed about the legality of placebos in EMS (I'll be looking it up in a few), but does anybody have any thoughts on this?

Most ethicists would view this as clinical experimentation without informed consent.

So here's an update. I talked to the EMT involved, and he said that they did it as a sort of placebo effect because "he was not in apparent resp. distress but was breathing at a 'normal' rate."

Is the ink dry on this idiot's termination paperwork yet? Also, this needs to be reported to the state EMS board.