cpap or bipap for status asthmaticus

[Painter1]

i've used bipap before, but today heard conflicting data about cpap being better in status.

any thoughts?

---

Members don't see this ad.

 

[logos]

Remember that its just for work of breathing. It dosen't fundamentally help fix their problem like it does in CHF. For me bipap makes more sense in terms of decreasing work of breathing. Less pressure to exhale against than CPAP. In fact, I can't really think of any circumstance were both were available I would choose CPAP over BiPAP.

 

[Aesculapius]

Simplistically, isn't CPAP more of a tool for oxygenation, and BiPAP more for ventilation? At least according to what I picked up during my ICU rotation.

 

[turkeyjerky]

I've always heard BiPAP for asthma, since the patients are so tired out by that point that they need assistance w/ the actual movement of air--can't really think of a good reason for CPAP in these patients ("splinting" the airways open sounds like BS to me).

Could you provide a link to the data you mentioned suggesting CPAP is superior?

 

[zinjanthropus]

I've used bipap successfully in a number of asthma patients that I expected to tube and then avoided intubation - sometimes pathophys and clinical reality just don't quite mesh up perfectly.

 

[Stitch]

All you're really doing with either modality is trying to meet the patient's own intrinsic auto PEEP, reducing the work of breathing. I've not seen any data on using CPAP, only bipap, likely because the delta p may give some ventilatory assistance. Whether this actually reduces systemic pCO2, I don't know.

What kinds of settings do you all usually use? At my shop we tend to use a narrow delta P, say 10/8 or 8/6. Again, I don't see much added benefit to a high delta p once you've matched the patient's auto PEEP.

 

[Aesculapius]

Wouldn't a small delta p be closer to CPAP?

 

[jdh71]

All you're really doing with either modality is trying to meet the patient's own intrinsic auto PEEP, reducing the work of breathing. I've not seen any data on using CPAP, only bipap, likely because the delta p may give some ventilatory assistance. Whether this actually reduces systemic pCO2, I don't know.

What kinds of settings do you all usually use? At my shop we tend to use a narrow delta P, say 10/8 or 8/6. Again, I don't see much added benefit to a high delta p once you've matched the patient's auto PEEP.

Agreed. Which is why, I'm not convinced CPAP is worse than BIPAP.

I don't like NIPPV in asthma. Maybe for 30-60 minutes if you're hoping the meds will kick in and break open the airways, but I can tell you that if a patient comes up from the ED into the MI sucking on BIPAP with a severe enough asthma exacerbation to find themselves in my unit, I'm going to intubate them, sedate them, and breathe for them until things calm down . . . unless they won't let me . . . in which case I'll just wait until their respiratory code and do it my way anyway. I just prefer the calmer, elective approach. Tubes go in and they can come out. It's not like intubation is a brain biopsy.

 

[Stitch]

Wouldn't a small delta p be closer to CPAP?

It would, and I tend to agree with jdh about cpap probably not being much different or worse. It's just that most of the data out there (that I'm aware of) is on bipap instead.

On the other hand, I'm MUCH more nervous about intubating an asthmatic. Maybe it's just kids, but we have very few respiratory arrests due to asthma (provided there's no tension pneumo) and I've always been taught never to intubate a pediatric asthmatic unless they are coding or unarousable. They ventilate themselves better than we can ventilate them. Even our senior PICU guys haven't had to intubate many asthmatics. Most of the ones I've cared for were intubated at outside facilities, and they come to us pretty sick. I've even put a couple on ECMO.

 

[EM2BE]

Agreed. Which is why, I'm not convinced CPAP is worse than BIPAP.

I don't like NIPPV in asthma. Maybe for 30-60 minutes if you're hoping the meds will kick in and break open the airways, but I can tell you that if a patient comes up from the ED into the MI sucking on BIPAP with a severe enough asthma exacerbation to find themselves in my unit, I'm going to intubate them, sedate them, and breathe for them until things calm down . . . unless they won't let me . . . in which case I'll just wait until their respiratory code and do it my way anyway. I just prefer the calmer, elective approach. Tubes go in and they can come out. It's not like intubation is a brain biopsy.

I have found in my few years so far that if I put a pt on BiPAP it's because they either don't want to be intubated or that they want to try something else first or that I want to see if meds help first. Usually within that 30-60min time frame, the patient gets better and are able to rest (maybe not completely wean off, but in that direction), or they get worse and have to be intubated.

 

[jdh71]

It would, and I tend to agree with jdh about cpap probably not being much different or worse. It's just that most of the data out there (that I'm aware of) is on bipap instead.

On the other hand, I'm MUCH more nervous about intubating an asthmatic. Maybe it's just kids, but we have very few respiratory arrests due to asthma (provided there's no tension pneumo) and I've always been taught never to intubate a pediatric asthmatic unless they are coding or unarousable. They ventilate themselves better than we can ventilate them. Even our senior PICU guys haven't had to intubate many asthmatics. Most of the ones I've cared for were intubated at outside facilities, and they come to us pretty sick. I've even put a couple on ECMO.

Interesting. Is this just dogma or is there data that intubation is worse in the pediatric population?

 

[Apollyon]

On the other hand, I'm MUCH more nervous about intubating an asthmatic. Maybe it's just kids, but we have very few respiratory arrests due to asthma (provided there's no tension pneumo) and I've always been taught never to intubate a pediatric asthmatic unless they are coding or unarousable. They ventilate themselves better than we can ventilate them. Even our senior PICU guys haven't had to intubate many asthmatics. Most of the ones I've cared for were intubated at outside facilities, and they come to us pretty sick. I've even put a couple on ECMO.

I've had to tube exactly one asthmatic in my career, and I felt like that was a failure. Early on in residency, the pulm guys where I was, who are as high powered as any, anywhere on the planet, drilled into us that, if you intubate an asthmatic, that is not the end of your problems, but just the beginning. With air trapping, using positive pressure on the lungs is like a room full of people, with a turnstile out, but not in, so as many as can get in, but only one at a time can leave. Now, what happens when that door in has people pushed in, irrespective of the number of people already inside?


I mean, I'm just a dumb ER doc, but primum non nocere.

 

[deleted109597]

Low dose ketamine, beta agonists, steroids, and PPV through a mask. They'll calm down and breathe better.
Maybe epi and mag. I mean, what disease exists that mag doesn't make a little better? Hypermag?

 

[docB]

Dang computer at work won't let me use multiquote.

So, to JDH I certainly hear what you're saying but it's actually constructive criticism about intubating asthmatics from our pulmo/CC guys that has made our group try longer with NIPPV. The rational, which makes sense to me, is that you have 2 problems. There's the fatigue and the airway constriction. Positive pressure, via mask or tube, only helps one. That's why the asthmatics are tough to manage on the vent with high pressures, low volumes, etc.

In EM we are getting exposed data, particularly on the prehospital side, that says kids in particular do worse with intubation. So again we're trying to save it for the cases where they failed a real attempt at NIPPV.

To Ninja Mag is even good for hypermag because it's our good clean mag rather than that suspect stuff they came in with. ***Note to students: I'm just kidding. DO NOT go give mag to a hypermag and say docB told you to.

 

[la gringa]

i'm w/ apollyon and veers - it's a personal loss to intubate an asthmatic. i've only tubed ONE - who failed an hr of bipap/mag/epi/low dose ketamine. he came in barely w/ any mental status and didn't get better. i had no choice!

i tend to follow my bad asthmatics that i bipap and send upstairs - most do just fine if i don't tube them downstairs. if there's a bad comorbidity like pna or MI or CHF then that's a different animal.... but straightforward asthma, for reasons cited above, is best managed w/o a vent.

 

[jdh71]

I've had to tube exactly one asthmatic in my career, and I felt like that was a failure. Early on in residency, the pulm guys where I was, who are as high powered as any, anywhere on the planet, drilled into us that, if you intubate an asthmatic, that is not the end of your problems, but just the beginning. With air trapping, using positive pressure on the lungs is like a room full of people, with a turnstile out, but not in, so as many as can get in, but only one at a time can leave. Now, what happens when that door in has people pushed in, irrespective of the number of people already inside?


I mean, I'm just a dumb ER doc, but primum non nocere.

Because NIPPV isn't positive pressure . . .

With all respect to the guys at Duke, the "don't intubate an asthmatic" is dogma and you intubate when you have to. You need to treat the patient.

 

[jdh71]

So, to JDH I certainly hear what you're saying but it's actually constructive criticism about intubating asthmatics from our pulmo/CC guys that has made our group try longer with NIPPV. The rational, which makes sense to me, is that you have 2 problems. There's the fatigue and the airway constriction. Positive pressure, via mask or tube, only helps one. That's why the asthmatics are tough to manage on the vent with high pressures, low volumes, etc.

Why would you need low volumes? And you expect high pressures. It's broncho-constriction

 

[Stitch]

Because NIPPV isn't positive pressure . . .

With all respect to the guys at Duke, the "don't intubate an asthmatic" is dogma and you intubate when you have to. You need to treat the patient.

I don't think anyone is arguing whether or not to 'treat the patient.' The issue is how to treat the patient. Is intubation better for the patient and when do you intubate? Or perhaps does mechanical ventilation truly correlate with increased mortality? Is there evidence that mechanical ventilation improves length of stay, asthma score or other parameters? Does intubation benefit or harm (or neither) the patient? I don't know. Obviously some people will buy themselves a tube.

I can say from experience that asthmatics in the pediatric population are quite difficult to manage. My suspicion is that a lot of the mortality is around induction, since you already have high intrathroacic pressures causing decreased preload. Even if you use ketamine, you're going to risk losing some amount of autopeep and more preload when/if you paralyze, risking decompensation. After that, even allowing for permissive hypercarbia and long expiratory times, they become quite acidotic (the ones I've seen have been in the 6.8-7.0 range). We have used THAM here as a buffer, but I'm not sure how truly effective that is. The bronchioles may take the brunt of the increased pressure needed to ventilate, but I've certainly seen more than one pneumothorax with a very fast decline in sats and blood pressure.

So in my practice, if I can struggle along with a spontaneously breathing patient who is protecting his airway, regardless of what the gas is (and I don't usually check), then I am unlikely to intubate because managing them on a vent is much worse/more difficult. Almost always, once those steroids kick in, they will turn around. If BiPap can make them more comfortable and buy me some time, I think it's worth it. In general I just don't believe we can ventilate them any better than the patient can ventilate himself. Just my thoughts, which have been consistent at the three institutions I've practiced in.

 

[jdh71]

I don't think anyone is arguing whether or not to 'treat the patient.' The issue is how to treat the patient. Is intubation better for the patient and when do you intubate? Or perhaps does mechanical ventilation truly correlate with increased mortality? Is there evidence that mechanical ventilation improves length of stay, asthma score or other parameters? Does intubation benefit or harm (or neither) the patient? I don't know. Obviously some people will buy themselves a tube.

I can say from experience that asthmatics in the pediatric population are quite difficult to manage. My suspicion is that a lot of the mortality is around induction, since you already have high intrathroacic pressures causing decreased preload. Even if you use ketamine, you're going to risk losing some amount of autopeep and more preload when/if you paralyze, risking decompensation. After that, even allowing for permissive hypercarbia and long expiratory times, they become quite acidotic (the ones I've seen have been in the 6.8-7.0 range). We have used THAM here as a buffer, but I'm not sure how truly effective that is. The bronchioles may take the brunt of the increased pressure needed to ventilate, but I've certainly seen more than one pneumothorax with a very fast decline in sats and blood pressure.

So in my practice, if I can struggle along with a spontaneously breathing patient who is protecting his airway, regardless of what the gas is (and I don't usually check), then I am unlikely to intubate because managing them on a vent is much worse/more difficult. Almost always, once those steroids kick in, they will turn around. If BiPap can make them more comfortable and buy me some time, I think it's worth it. In general I just don't believe we can ventilate them any better than the patient can ventilate himself. Just my thoughts, which have been consistent at the three institutions I've practiced in.

Well bad asthma is bad asthma. And asthmatics in any population can be difficult to manage. Maybe the pediatric population is that much more pre-load dependent? THAM is a very effective buffer if the beans are working fine. You can also buffer them with cvvhd. Alternatively ECOR. If you've got ECMO, you've got ECOR. We've all seen pneumos on a vent - it's the cost of doing business, and we also know how to handle them.

Look, I didn't argue against the use of NIPPV, quite the contrary, but I've seen too many of these bad asthmatics come up sucking on the BIPAP putter out and try and die on me, right before my very eyes. We try and push it for many of the reasons you bring up, and for my money, if thing do not look like they are turning around any time soon (I've see it take 3-5 days for things to break open and that's on a boat od methylpred, continuous albuterol, mag, theophylline - hell we even talked them into bleeding in surgical anesthetic), I prefer the calm and easy to the "holy ****!! she just stopped breathing, someone call a code!!!"

 

[EctopicFetus]

Because NIPPV isn't positive pressure . . .

With all respect to the guys at Duke, the "don't intubate an asthmatic" is dogma and you intubate when you have to. You need to treat the patient.

I believe when this was discussed on EMRAP 25% of asthmatics who get tubed.. die..

Not sure that I remember that correctly or if I do remember it correctly that it is accurate but there it is.

 

[jdh71]

I believe when this was discussed on EMRAP 25% of asthmatics who get tubed.. die..

Not sure that I remember that correctly or if I do remember it correctly that it is accurate but there it is.

Asthmatics that sick do, too often, die . . .

 

[Apollyon]

Because NIPPV isn't positive pressure . . .

With all respect to the guys at Duke, the "don't intubate an asthmatic" is dogma and you intubate when you have to. You need to treat the patient.

I wasn't talking about NIPPV. And the pulm guys were creating new dogma - that's why the staff was never inbred - they were always creating new research. One of the most outspoken (and, to be honest, abrasive) pulm guys said one day that the thing that saved asthmatics wasn't heliox, wasn't steroids, wasn't intubation - but close observation in an ICU. On further description, he meant moment by moment management, which may include any of the above, or other things. It's the time unit one uses to manage. If it is every hour, you may really fail. If it is every 10 minutes, you're less likely. If it is every minute, you're right on top - and, if you tube that patient, you'll need q10 or q5min re-evaluation. That's why any EM doc here will tell you that an asthmatic is an "easy" patient on whom to bill critical care, even if the patient ends up being discharged. The in extremis asthmatic ups my pucker factor more than an MI, because, if the heart stops, we push on the chest. If the asthmatic stops, though, it is NOT easy to breathe for them.

Listen, friend - I am not pursuing some passive-aggressive agenda against you. It's just that tubing the asthmatic is not the slam dunk like tubing the code. It's not the panacea as it is in other cases. The tube in the asthmatic does not decrease the tension or fear (in me, at least) - it's not an end-point where I can temporarily relax and unclench. It's that fear that the tube goes in, and the air isn't moving, and we can't do anything else. It's that absolute feeling of being powerless despite doing everything right and quickly.

 

[Rendar5]

Well bad asthma is bad asthma. And asthmatics in any population can be difficult to manage. Maybe the pediatric population is that much more pre-load dependent?

Not entirely sure of the physiology with kids, but there is a 10% code rate associated with intubation and switch from negative to positive pressure. I'm 1 for 1 with my PICU population (CO2 of 110 kinda forced the issue). Kid brady'd to 50 and required CPR for about a minute within 30 seconds of tubing.

 

[jdh71]

I wasn't talking about NIPPV. And the pulm guys were creating new dogma - that's why the staff was never inbred - they were always creating new research. One of the most outspoken (and, to be honest, abrasive) pulm guys said one day that the thing that saved asthmatics wasn't heliox, wasn't steroids, wasn't intubation - but close observation in an ICU. On further description, he meant moment by moment management, which may include any of the above, or other things. It's the time unit one uses to manage. If it is every hour, you may really fail. If it is every 10 minutes, you're less likely. If it is every minute, you're right on top - and, if you tube that patient, you'll need q10 or q5min re-evaluation. That's why any EM doc here will tell you that an asthmatic is an "easy" patient on whom to bill critical care, even if the patient ends up being discharged. The in extremis asthmatic ups my pucker factor more than an MI, because, if the heart stops, we push on the chest. If the asthmatic stops, though, it is NOT easy to breathe for them.

Listen, friend - I am not pursuing some passive-aggressive agenda against you. It's just that tubing the asthmatic is not the slam dunk like tubing the code. It's not the panacea as it is in other cases. The tube in the asthmatic does not decrease the tension or fear (in me, at least) - it's not an end-point where I can temporarily relax and unclench. It's that fear that the tube goes in, and the air isn't moving, and we can't do anything else. It's that absolute feeling of being powerless despite doing everything right and quickly.

The extremis asthma patient should make everyone pucker. This is one of the hardest acute presentations to treat. It's going to be hard to breathe for these patients regardless - no air moving in is irrelevant here actually because it's one of the unfortunate end points. If the air isn't moving in, then you still haven't done yourself or anyone else any favors by not intubating them anyway. I never said it was a slam dunk, nor a panacea. And if you look at the physiological vent data on asthma, funny or fancy vent manuevers don't help nor really matter. You match the auto-peep and breathe per essentially normal vent settings with lower rates handling the acidosis as you are able with CVVHD, THAM, or even ECOR (ECMO). Pray that the meds kick in.

The problem in super acute asthma isn't the vent or the NIPPV it's the broncioles. It's like bad AS or horrible decompensated right heart failure - all your interventions are sitting on the WRONG side of the physiology at baseline. Most of this is style, and I would say the point of view of the EP is a bit different than that of the Pulm/Crit guy - and yes - the dogma for years was don't intubate these people if you can help it. But I've had the priviledge to sit at the feet of someone who has published extensively in the critical care literature on asthma and the ventilator and learn, and he said he no longer feels so strongly about the "don't intubate at all costs" dogma. His point: bad asthma is bad asthma - we go round and round and roud about it, but the vent vs NIPPV vs whatever is probably moot. He's the best damn critical care clinician I've ever worked with from the perspective of physiology and intervention as they apply at the bedside. So we all have our training biases.

 

[leviathan]

I mean, what disease exists that mag doesn't make a little better? Hypermag?