# Flow Rates



## mikie (Apr 3, 2008)

All of the regulators on our O2 tanks go up to 25lpm.

When is that used?  That's quite bit of oxygen flowing... I've heard from some one that they've used it on a BVM before.  Is that true? 

Also, is there any prehospital use for <2lpm? (1/4, 1/2)

Thanks!


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## MMiz (Apr 3, 2008)

You need to check your protocols.  I would not use it on a BPM.  15 LPM all you need.


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## EMTMandy (Apr 3, 2008)

MMiz said:


> You need to check your protocols. I would not use it on a BPM. 15 LPM all you need.


 

I agree. especially if you're using a portable tank. You will blow through it really fast and it isn't necessary


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## Ops Paramedic (Apr 3, 2008)

If you calculate the flow rate for a average weighing adult, lets say 75 kg (Don't have the formula in pounds), at a 12 breaths per minute= (6-8ml Tidal vol/Kg)*(Respiration rate), you will get: 5,4 l/min (Using all the values at the bottom ranges).  Even if you up these values to 100kg patient at a TV of 10ml/kg (Outdated value), and up the RR to 20/min, you will still only get to: 20l/min.  This formula does not take into consideration the dead space effect.  

So no, you should not get up 25l/min in theory, when using a BVMR.  However, should you use a BVMR (Not connected to an ETT), and don't maintain a good seal, or perhaps ventilate the stomach, you might need more than 25l/min, as it not goinig where it is supposed to go!!  Using the same formula, you can get up to the 25l/min mark with a patient who is presenting with tachypnea, and a large adult (TV is may increase with this as well) and you administer O2 via mask with a reservoir.  Eg. (80kg*10ml/kg)*(30RR)= 2,4l/min.  So by using a mask, you may get closer, that with BVMR because you will not likely hyperventilate the patient on a BVMR

Our protocol state that we should use 15l/min on a BVMR, i don't follow that.  I use a flow rate that is enough to keep the reservoir bag infalted between ventilations, then i am not giving to little or to much.

As for 2l/min, yes there is a place prehospital.  You will use this flow rate on patients at the extreme end of the age scale, i.e. the geriatrics an neonates.  Maybe not on the primary/emergency response call, but for sure the transfers/stepdowns, when these patient come from instutions where they are use to these type of flow rates.


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## VentMedic (Apr 3, 2008)

The valve structure on most disposable BVMs is not designed to withstand much more than 15 L/M.  

pet peeve: "flush" flowmeter on a BVM in the hospital 

Some of the "CPAP" masks are running a 25 L flow instead of the 50 PSI  outlet.

As Ops mentioned, some patients may need a minute volume of 25 L/m


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## mikie (Apr 3, 2008)

MMiz said:


> You need to check your protocols.  I would not use it on a BPM.  15 LPM all you need.



That's what I thought.  I was just curious as to the application of 25lpm.


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## CFRBryan347768 (Apr 3, 2008)

When You get your Frequent Flyer that says,"this ******* thing aint workin crank it allll the way up!!" hah


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## LucidResq (Apr 3, 2008)

mikie333 said:


> Also, is there any prehospital use for <2lpm? (1/4, 1/2)



I would kick your *** if you put me on a nasal cannula on anything over 2 lpm. Maybe it's just me, but anything more than that is extremely uncomfortable. Feels like a freaking tornado in my nose.

I don't about using a flow rate below 2 lpm, though.


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## VentMedic (Apr 3, 2008)

mikie333 said:


> Also, is there any prehospital use for *<2lpm? (1/4, 1/2)*
> Thanks!



If you transport an infant or pediatric from home or to home, that may be their liter flow.

Some adults may also be on only 1 or 1.5 L as discharge from the hospital or transport from home provided it is not a respiratory distress situation.


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## mikie (Apr 3, 2008)

LucidResq said:


> I would kick your *** if you put me on a nasal cannula on anything over 2 lpm. Maybe it's just me, but anything more than that is extremely uncomfortable. Feels like a freaking tornado in my nose.
> 
> I don't about using a flow rate below 2 lpm, though.



I was taught never more than 4!

And I agree!  (I'm on an ILS truck, so there is always a higher ranking person) I'm usually told 4lpm on a pt in 'minor' distress.  I chose 2lpm if they don't 'need' it, but I feel more comfortable erring on the side of caution.

My protocol:


> 15 L/min via non-rebreather mask or *6L/min via nasal cannula *if the patient does not tolerate a mask


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## JPINFV (Apr 4, 2008)

Nasal cannula is 1-6 liters. NRB flow rate is enough to keep the bag from deflating (normally 10lpm will work). The difference a lot of the time between 10 and 15 liters per minute is the speed at which you empty your tank. It's not lazy if extra effort doesn't accomplish anything. 

As far as oxygen, either the patient can/might benefit from it or can't. I don't follow the "everyone gets oxygen" theory. If a patient doesn't need it, then why is anyone administering it? In general, if there is no resp. distress I don't use a NRB and instead opt for a NC set between 2-6 depending on the presentation.


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## mikie (Apr 4, 2008)

JPINFV said:


> As far as oxygen, either the patient can/might benefit from it or can't. I don't follow the "everyone gets oxygen" theory



I agree.  A small fx on the arm doesn't usually warrant O2

but of course, I'll err on the side of caution.  I don't think I'll get a slap on the wrist if I give O2 versus not!


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## Arkymedic (Apr 4, 2008)

mikie333 said:


> I agree. A small fx on the arm doesn't usually warrant O2
> 
> but of course, I'll err on the side of caution. I don't think I'll get a slap on the wrist if I give O2 versus not!


 
Well lets think about what happens before you say it does not warrant O2. I do not know about you, but when I have had my Fx's I was in a helluva lot of pain. Oxygen encourages the pt to calm their breathing as the fight or flight system is producing extra adrenaline. Pt's with fx's are usually wound up and breathing hard due to the extra sensations and the psychological response that accompanies pain. As the HR increases and depending on the type of the fx, the pain level and tolerance; Pt's can give themselves chest pain, respiratory distress, etc. This can lead to an increased preload and oxygen demand, etc. As we all know every pt is different and pain is different for all; however, the benefit of oxygen should never be withheld.


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## mikie (Apr 4, 2008)

Arkymedic said:


> however, the benefit of oxygen should never be withheld.



Couldn't agree more!


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## JPINFV (Apr 4, 2008)

Arkymedic said:


> Well lets think about what happens before you say it does not warrant O2. I do not know about you, but when I have had my Fx's I was in a helluva lot of pain. Oxygen encourages the pt to calm their breathing as the fight or flight system is producing extra adrenaline. Pt's with fx's are usually wound up and breathing hard due to the extra sensations and the psychological response that accompanies pain. As the HR increases and depending on the type of the fx, the pain level and tolerance; Pt's can give themselves chest pain, respiratory distress, etc. This can lead to an increased preload and oxygen demand, etc. As we all know every pt is different and pain is different for all; however, the benefit of oxygen should never be withheld.


Which is why Fx patients deserve proper pain management, thus making them paramedic calls.


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## paramedix (Apr 4, 2008)

Some of the masks have a setting printed on it. Eg. Venturi 60% @ 5l/min, if you set your tank flow rate anything above that, you just wasting the o2, it will still deliver 60%, but if you go under 5l/min you will not receive 60%.

Also keep your setting to keep the reservoir bag filled 2/3 and it doesnt collapse during inspirations.

Our protocol states 15l/min, but have found that on some BVM's, 10-12l/min is more than enough to keep the reservoir inflated.


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## VentMedic (Apr 4, 2008)

Flowrates are not going to mean the same for two different people.  2 L/min or even 6 will not deliver the same amount (concentration, FiO2, %) of oxygen to different individuals or even to the same individual if they vary their respiratory rate or pattern.   That is why the "give  2L for this" recipe is not always appropriate.

A NRBM is also not actually a high flow device by definition in many situations.  A high flow device must be able to provide for the patient's total minute volume while maintaining a stable oxygen concentration.  

Hospital masks that do provide high flow may start at 15 - 25 L/min with the ability to entrain 5 - 20 L/min of room air in a venturi mix to satisfy the patient's minute volume requirement.  For those that don't tolerate face masks, there are high flow nasal cannulas that can run up to 32 - 40 liters/minute depending on the manufacuter.  These systems require special humidification systems and are actually very comfortable.


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## emtwacker710 (Apr 4, 2008)

yea most of our tanks here only go to 15lpm, although I think we have 2-3 regulators laying around that go up to 25lpm, I feel that there is no need for that, 15lpm is all you need for most situations, but yes, check your local protocals and see what they say, also ask around at your acency and see what others there say.


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## Arkymedic (Apr 4, 2008)

JPINFV said:


> Which is why Fx patients deserve proper pain management, thus making them paramedic calls.


 
I fully agree with that and I was just trying to illustrate the importance of oxygen that way too many discount.


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## TKO (Apr 6, 2008)

We go 2-4 Lpm (nasal), 6-10 (simple/adult face mask), 10-15 (NRB), 15-25 (BVM).

On routine call, pt sats >96%, pink and perfusing, A+O, no dyspnea complaint, warm, no significant complaint, no treatments performend and a 10 minute ride to the hospital and I won't admin O2.  If O2 will give any visible benefit, like calming or placebic, then I'll revise that decision.  But otherwise, there are numerous times a pt doesn't require supplemental 02.

I believe O2 is severely underestimated.  So many EMS personnel want to give the fancy drugs and really don't see the value of proper oxygenation.  I don't have the stats to back it up, and is just an educated guess, but I would comfortably wager proper oxygenation has saved more pts than IV therapy has, and is thusly more valuable as treatment.


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## MSDeltaFlt (Apr 6, 2008)

TKO, I have converted more pts from lethal dysrhythmias with O2, vagals, or fluid than with IV drugs and electricity.


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## NRNCEMT (Apr 12, 2008)

What I've been taught is as follows:

36 L/M Vent C-PAP or biPAP @ 50 L/M

2-6 L/M NC

15 L/M NRB

15 L/M BVM


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## VentMedic (Apr 12, 2008)

NRNCEMT said:


> What I've been taught is as follows:
> 
> 36 L/M Vent C-PAP or biPAP @ 50 L/M



What machine are you using?


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## TKO (Apr 15, 2008)

MSDeltaFlt said:


> TKO, I have converted more pts from lethal dysrhythmias with O2, vagals, or fluid than with IV drugs and electricity.



TESTIFY!

Still, everyone wants to go in there with an IV in the arm and get the ED to sign their PCRs for the meds they gave.

I just had a chest pain call and my pt couldn't do ASA and no nitro.  She refused Entonox for pain relief.  My partner started her on high-flow 02 (NRB) and I left her there.  She said the pain was going away about 10 minutes later.  I went for an IV but no luck there.  Got to the big H and the triage nurse asked me why I had her off the 02 (just from the back of the truck to a bed) and I said she was satting at 100% with no SOB or further pain complaint and no acute distress (I could have put her on the portable, but where was the need for 3 minutes?).  The next nurse asked why I had her on high-flow.  I explained that I couldn't do anything else for her so the high-flow was what I had left and it worked just fine.

And usually does.  Why go down to a nasal?  Why maintain the chest pain when high flow can often alleviate it?

Oxygen, baby!  It'll save your life.


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