- Joined
- Mar 16, 2006
- Messages
- 214
- Reaction score
- 0
i've used bipap before, but today heard conflicting data about cpap being better in status.
any thoughts?
any thoughts?
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.
Wouldn't a small delta p be closer to CPAP?
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.
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.
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.
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.
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.
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.
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.
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?
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.
I mean, what disease exists that mag doesn't make a little better? Hypermag?