# CPAP  and BiPAP in asthma



## zzyzx (Oct 14, 2014)

I understand that the only function for CPAP in asthma is to reduce the work of breathing, and that the current evidence appears to show benefit in its use for severe exacerbations, but doesn't it contribute to air trapping?

If you can use BiPAP (which we don't have pre-hospital), would you use the lowest end expiratory pressure in order to reduce air trapping?


----------



## DrankTheKoolaid (Oct 15, 2014)

Weingart does a great podcast explaining this subject. 

Look up the episode labeled coding asthmatic if I remember right.

End result is CPAP is of questionable use, while the inhalation support from Bipap is a definite use


----------



## DPM (Oct 25, 2014)

I've had very responses when using CPAP in conjunction with Albutarol and Atrovent. Also, saying "only function" does make it sound like it's not that useful, which is not something that I would agree with. BIPAP with a low exp. pressure would be most beneficial, but I don't know any pre-hospital providers in my area that can provide that.


----------



## FiremanMike (Oct 27, 2014)

My experience is that it works "sometimes".  It is worth a try on some COPD/Asthma patients, but don't become over-reliant and ignore the fact that some of these patients will need to be intubated anyway.  Increasing their SpO2 via CPAP to 95% means nothing if they are becoming semi-responsive or show now change in work of breathing.  

Everyone here has seen a medic who's left their patient on CPAP 'because the sats were coming up', despite the fact that the patient is still in severe respiratory distress and stating no improvement.  Don't be that medic.


----------



## ThadeusJ (Oct 27, 2014)

At the moment the only way to provide Bilevel NIPPV (because BiPap is a brand name for a particular device providing a particular mode) is through a mechanical ventilator in non-invasive mode (LTV, Draegar, etc.).  It will also consume a lot more oxygen resources that the CPAP devices.  Up till a few years ago, the patient outcome studies didn't show a significant difference between CPAP and Bilevel, but you are correct in that any application of positive pressure may exacerbate air trapping.  The idea between applying it, however, is that you decrease the pressure differential between the trapped air and the "outside" air while creating a pneumatic stent within the airways, keeping them open and allowing gas exchange to occur.  

Similar to air leaving a balloon trying to get past the collapsed passage where you blow in.  If you stent that passage, the air in the balloon can rush out faster.  At least that's the theory.


----------



## Carlos Danger (Oct 27, 2014)

FiremanMike said:


> My experience is that it works "sometimes".  It is worth a try on some COPD/Asthma patients, but don't become over-reliant and ignore the fact that some of these patients will need to be intubated anyway.  Increasing their SpO2 via CPAP to 95% means nothing if they are becoming semi-responsive or show now change in work of breathing.
> 
> Everyone here has seen a medic who's left their patient on CPAP 'because the sats were coming up', despite the fact that the patient is still in severe respiratory distress and stating no improvement.  Don't be that medic.



Sure there are times that NIPPV won't work and these folks will end up intubated. But if their sats are improving than by definition their gas exchange is improving. It might not still be where it needs to be and they might still end up tubed, but if nothing else you've bought some time to hopefully get to the ED and a more controlled environment with more help.


----------



## Carlos Danger (Oct 27, 2014)

What FEV1 indicates the need for intubation in an asthmatic?

What PaC02?


----------



## ThadeusJ (Oct 28, 2014)

If a patient can actually perform a reproducible FEV1, then you have a while to go before they need tubing.  Like the original question asks about applying positive pressure on an asthmatic, tubing them and forcing more air in ain't gonna be much better unless you are really really deep in the weeds.  I would avoid tubing them at all costs and devote all my energy into reversing the bronchospasm.  Follow the PaCO2, but don't tube based on a number.  People can survive high CO2 levels, but only for so long.  Follow the trend, consider co-morbidities and watch the patient.

But thats just me.


----------



## FiremanMike (Oct 28, 2014)

Remi said:


> Sure there are times that NIPPV won't work and these folks will end up intubated. But if their sats are improving than by definition their gas exchange is improving. It might not still be where it needs to be and they might still end up tubed, but if nothing else you've bought some time to hopefully get to the ED and a more controlled environment with more help.



Treat the patient and not the monitor.


----------



## chaz90 (Oct 28, 2014)

FiremanMike said:


> Treat the patient and not the monitor.


I hope there's a missing *sarcasm* tag here. Agreed that there are certainly times intubation could still be necessary even with improving sats, but Remi's statements are accurate.


----------



## FiremanMike (Oct 28, 2014)

chaz90 said:


> I hope there's a missing *sarcasm* tag here. Agreed that there are certainly times intubation could still be necessary even with improving sats, but Remi's statements are accurate.



No missing sarcasm, I don't want people to think that increasing sats are "good enough".. As we advance further and further into the integration between technology and medicine, we need to remain vigilant to not look at a number out of context (i.e. SpO2) and use it as the determining factor for patient improvement.

Believe me when I say I mean neither arrogance nor condescension with my post, I am passionate about the improvement of EMS delivery.  Sometimes I may come across as crass, it's unintentional.


----------



## Carlos Danger (Oct 28, 2014)

FiremanMike said:


> Treat the patient and not the monitor.



I give up.


----------



## ThadeusJ (Oct 28, 2014)

Actually this is a very good point as it applies to CPAP because (as was alluded to) almost every study shows that CPAP prevents intubation 30-50% of the time...meaning it _doesn't_ work to prevent intubation 50-70% of the time.  At what point the patient activates EMS, the pathology, co-morbidities and the effectiveness of the device itself are all factors in the success or failure of this therapy.  Of course saying "treat the patient not the monitor" is commonplace and logical, I think what it means here is that CPAP therapy is more of an art than a science and numbers are best for trending than making any conclusions about reaching an end point.


----------



## FiremanMike (Oct 28, 2014)

Remi said:


> I give up.



k


----------



## DesertMedic66 (Oct 28, 2014)

FiremanMike said:


> Treat the patient and not the monitor.


How about we treat the patient and then monitor? Technology provides us with information that we are unable to have by just looking at the patient....


----------



## FiremanMike (Oct 28, 2014)

We're now kinda getting to the point where my statement is being taken out of context and my point is being missed..


----------



## Brandon O (Oct 31, 2014)

Remi said:


> What FEV1 indicates the need for intubation in an asthmatic?
> 
> What PaC02?



Who's measuring either in the field?


----------



## TransportJockey (Oct 31, 2014)

Brandon O said:


> Who's measuring either in the field?


I can and do monitor paco2 as part of my chem 8+ in the field. Especially with my critical respiratory patients


----------



## Carlos Danger (Oct 31, 2014)

Brandon O said:


> Who's measuring either in the field?



It was just trivia.


----------



## usalsfyre (Nov 2, 2014)

ThadeusJ said:


> At the moment the only way to provide Bilevel NIPPV (because BiPap is a brand name for a particular device providing a particular mode) is through a mechanical ventilator in non-invasive mode (LTV, Draegar, etc.).  It will also consume a lot more oxygen resources that the CPAP devices.


Negative Ghostrider, the majority of advanced vents are far more friendly to O2 supplies than CPAP devices, outside high demand patients. And in those patients your CPAP was likely unable to meet the flow.


----------



## usalsfyre (Nov 2, 2014)

FiremanMike said:


> We're now kinda getting to the point where my statement is being taken out of context and my point is being missed..


This statement is taken out of context more than it is taken in context, hence the hate. "Assess your patient and correlate findings" is a much better way of saying this than a hackneyed EMS saying.


----------



## usalsfyre (Nov 2, 2014)

FiremanMike said:


> My experience is that it works "sometimes".  It is worth a try on some COPD/Asthma patients, but don't become over-reliant and ignore the fact that some of these patients will need to be intubated anyway.  Increasing their SpO2 via CPAP to 95% means nothing if they are becoming semi-responsive or show now change in work of breathing.
> 
> Everyone here has seen a medic who's left their patient on CPAP 'because the sats were coming up', despite the fact that the patient is still in severe respiratory distress and stating no improvement.  Don't be that medic.


I'm gonna be highly hesitant to intubate an obstructive patient with improving physiologic parameters. HIGHLY. All I'm doing in the case of NPPV is buying time for the meds to work. I'm going to pull out the big gun meds like mag and epi drips before I tube this patient. By the same token of treat the patient and not the monitor....sometimes patients are unreliable.


----------



## systemet (Nov 3, 2014)

Remi said:


> What FEV1 indicates the need for intubation in an asthmatic?
> 
> What PaC02?



Just to be the obvious guy:

Whatever PaCO2 / FEV1 at which the patient continues to deteriorate, and is either (1) showing signs of fatigue despite maximal medical therapy, or (2) is becoming progressively altered to the point that it's either interfering with patient care or there becomes potential for aspiration.


----------



## Carlos Danger (Nov 4, 2014)

I posted the questions simply as trivia. I was reviewing that topic myself for an exam, and thought a couple people might learn something looking it up and maybe find it interesting. 

Instead, everyone seem to default to "I'll just tube 'em when they need it". Oh well. "Treat the patient, not the monitor, right"?


----------



## systemet (Nov 4, 2014)

Remi said:


> I posted the questions simply as trivia. I was reviewing that topic myself for an exam, and thought a couple people might learn something looking it up and maybe find it interesting.
> 
> Instead, everyone seem to default to "I'll just tube 'em when they need it". Oh well. "Treat the patient, not the monitor, right"?



It looks like I completely missed the point!  Sorry.

My understanding, from talking to some critical care and ER physicians who are much smarter than me, is that there's not really a specific PaCO2 or pH at which intubation is mandatory, providing the patient is maintaining their airway, and is maintaining or improving.

I think someone else already made a good point about the FEV, to the point of, if they can perform dynamic spirometry, then they don't need to be intubated yet, i.e. they're compliant / obeying commands.

What I was taught, is that intubation is to be avoided for as long as possible, and that it is there to maintain the airway when the patient cannot, to assist ventilation when they fail, and is not going to address any of the underlying issues, which are a function of airway resistance that needs to be addressed pharmacologically.

This isn't to say that these numbers aren't useful; they provide objective information about the patient's ventilatory status, which can be correlated with subjective clinical findings.

https://www.ebmedicine.net/topics.php?paction=showTopicSeg&topic_id=59&seg_id=1860
http://www.anesthesia.org/winterlude/wl95/wl95_8.html
http://emcrit.org/podcasts/vent-part-2/
http://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&cad=rja&uact=8&ved=0CEUQFjAE&url=http://www.emergpa.net/wp/wp-content/uploads/2011/03/asthma-intubation.pdf&ei=C4NZVPWuC8eQyATM1oLQDA&usg=AFQjCNF2PhNAQzjRu9dY2hyg_SWWU6fWeg
http://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&cad=rja&uact=8&ved=0CE4QFjAF&url=http://www.thoracic.org/statements/resources/allergy-asthma/asthma.pdf&ei=C4NZVPWuC8eQyATM1oLQDA&usg=AFQjCNHTK86I1kp0-d_8TGyHRmRFsJT2GQ

* _Looking through some of these resources, it seems like there's a consensus that pH < 7.20 is probably a sufficient reason to intubate. This probably corresponds to a PaCO2 ~> 55mHg, that being said, the majority of physicians I've talked to have said that they base their decision as to whether to intubate on physical exam findings and whether they've already exhausted other options._


----------



## Jeff Rehman (Nov 5, 2014)

BiPAP is indeed more appropriate but I believe that one of the best (albeit somewhat Draconian) techniques the medic can employ would be to gently FORCE exhalations
with the patient so long as they re awake and understand what you're doing and why.
The 'bear hug' has it's place in assisting to release trapped dead air, affording the space to introduce more O2 and bronchodilators.  If their LOC or work of breathing becomes too compromised, then the lost art of NASAL INTUBATION should be employed as the work of breathing needs to be totally assumed by the provider. In these cases I usually administer a couple mG of Versed (midazolam) to chill the patient out and get him/her to trust that we won't let them down in terms of breathing for them.
Nebulizing in Albuterol and Atrovent go, of course, without saying...  But the early administration of Solu-Medrol and even MGSO4 if Epi isn't indicated- are crucial. Normalizing the ETCO2 readings take a front seat here, as I've come to learn in my eld.   I've seen that the early administration of Ketamine (sedative and bronchodilator as well) in the ER - is wonderfully effective in bringing that totally shut-down patient back into the fold.


----------



## Carlos Danger (Nov 5, 2014)

systemet said:


> It looks like I completely missed the point!  Sorry.
> 
> My understanding, from talking to some critical care and ER physicians who are much smarter than me, is that there's not really a specific PaCO2 or pH at which intubation is mandatory, providing the patient is maintaining their airway, and is maintaining or improving.
> 
> ...




Certainly no reason to apologize.

The answers to the original question:

Fev1 = <25% of normal
Pc02 =  >50mmHG despite aggressive bronchodilator therapy

_Stoelting's Anesthesia & Coexisting Diseases
_


----------



## FiremanMike (Nov 10, 2014)

Remi said:


> I posted the questions simply as trivia. I was reviewing that topic myself for an exam, and thought a couple people might learn something looking it up and maybe find it interesting.
> 
> Instead, everyone seem to default to "I'll just tube 'em when they need it". Oh well. "Treat the patient, not the monitor, right"?



What is it about these trade forums that inevitably brings out the **** measuring contest on every topic possible.  I'm not really sure why we couldn't have a mature and enlightening discussion where perhaps people could learn from our collective experience?  Instead, you go directly for arrogant vitriol in an effort to show everyone how much you know..


----------



## FiremanMike (Nov 10, 2014)

usalsfyre said:


> I'm gonna be highly hesitant to intubate an obstructive patient with improving physiologic parameters. HIGHLY. All I'm doing in the case of NPPV is buying time for the meds to work. I'm going to pull out the big gun meds like mag and epi drips before I tube this patient. By the same token of treat the patient and not the monitor....sometimes patients are unreliable.



Despite the way my words are interpreted, I am always highly hesitant to intubate anyone, but I'm also not afraid of it.  The scenarios I speak of (medics leaving patient's on CPAP despite no patient improvement) are not necessarily the norm, but they also aren't uncommon.  The latest information I knew said that CPAP in COPD/emphysema/severe asthma wasn't really concrete and that it "works sometimes, not always, and we're not really sure why", and this has mirrored my own experience with CPAP in those patients.  Obviously CHF is a different story...

The specific scenario I spoke of was, to date, a once in a lifetime run.  A patient with a previous history of intubations for exacerbations, in respiratory failure, and not responding to treatments other than his SpO2 increase.  At the point I decided to sedate and intubate him, he was obtunded and diminished, he didn't even have enough energy to hold the nebulizer in his mouth (he was in relatively good shape for a COPDer, this finding was unexpected).  The case was reviewed by the EMS supervisor and then the medical director who had access to the patient's in-hospital report, both agreed that intubation was the right choice in this patient.  My respiratory protocol includes epi, mag, and decadron beyond albuterol/atrovent and I can and have used different treatment methods in different patients.

Perhaps I was too flippant with my "treat the patient and not the monitor" and you are correct that sometimes you should consider treating the monitor and not the patient.  The most universal statement on this thread so far is to treat both the monitor and the patient, which is always the best way to practice.

Remember guys and gals, there are new and inexperienced medics who read these forums.  We should all take a step back and realize that those of us with a bit of experience have a lot to offer those new folks and should spend our time educating them and each other as opposed to bickering.

tl:dr - The original point I was trying to make before this thread devolved to its current state is that we cannot be dependent on CPAP to fix our COPD/emphysema/asthma patients.  It might work, but maintain vigilant in monitoring your patient and don't be afraid to back off your current treatment and move on to the next.


----------



## Carlos Danger (Nov 10, 2014)

FiremanMike said:


> What is it about these trade forums that inevitably brings out the **** measuring contest on every topic possible.
> 
> Instead, you go directly for arrogant vitriol in an effort to show everyone how much you know..



If that is directed towards me, I don't know what you are talking about.

You might want to read back through the thread and see who was responding to whose posts with BS.


----------



## FiremanMike (Nov 10, 2014)

On second thought, 2 way communication is just not possible..


----------

