8 y/o Severe brochospasm scenario
- Thread starter mc400
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Gotta chime in here.
CPAP is indeed a good choice for the status asthmaticus pt. The physiology is this: In a bronchostrictive event, the bronchiolies are swollen, mucous covered, and in spasm. Since inhalation is an active phase, the inhaled air is forced through the bronchiolies into the alveoli. However
During exhalation (passive), the bronchiolies close off and the air is trapped in the alveoli where it becomes O2 depleted. (Think of a woopie cushion)
So: CPAP increases airway pressures on the exhalation phase (well both actually but just stick with exhalation). By keeping some "backpressure" in the bronchiolies, it effectively splints them open. In this way, it recruits alveoli, reduces air trapping, and actually reduces the chance of a pneumothorax. This increases tidal volumes, reduces terminal airway pressures, improves oxygenation, and improves ventilation (getting rid of C02).
http://chestjournal.chestpubs.org/content/123/4/1018.full
http://chestjournal.chestpubs.org/content/125/3/1081.full
http://www.ncbi.nlm.nih.gov/pubmed/11355116?dopt=Abstract
Smash
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Whilst there may be potential for non-invasive mechanical ventilation to become part of the treatment of severe, acute asthma, I think we are a long way to go before we can or should say that it is a good choice.
There is an absolute lack of data for the safety and efficacy of NIMV at this stage. The references you have supplied and that are linked in the Chest journal are interesting, but they do nothing more than suggest a course for further research.
The Fernandez study enrolled only 22 patients, was retrospective and observational and allowed bias in that the ICU Dr decided whether or not to utilize NIMV or intubate. It was also set in an ICU, so it may not be applicable to emergent or prehospital settings.
Sorosky produced an interesting pilot study that at least was randomized, but again, in an ICU setting and utilizing BiPAP, which is not commonly available in the field, rather than CPAP, which is what most of us are carrying. It also had a very small sample size (N=33) and did not actually compare with standard treatment or placebo. Treatment was also stopped to give nebulizers.
The only other article that the Chest review quotes is Meduri's trial with a VERY small sample size (N=17), BiPAP rather than CPAP, ICU rather than ED or field setting and again is retrospective.
There is an absolute dearth of papers on this, and the ones that do exist have appallingly low numbers of patients enrolled. The larges is Beers 2005 one I think, with about 80 patients, but it was not worth the paper it was written on.
The physiology might sound compelling, but as we discover on nearly a daily basis, what we think sounds good from a physiological standpoint often ends up being really bad for patients in the real world.
The jury is very much still out, or indeed has not even been sworn in yet, when it comes to CPAP in acute asthma, and I would certainly not be treading that path myself without a lot more data to back me up.
Shishkabob
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Meh, CPAP is much like intubation in this case: Not the most ideal solution, but if it works, than great, especially if you can do inline beta-agonist. Give it a quick trial before you move on to RSI.
I've done CPAP on an asthma patient before and it was fantastic, sudden turn around that helped the patient. Granted the agency I was with didn't have RSI so it was all we had to give it a shot.
Just like intubation / RSI... the problem isn't getting air in, it's getting it out, but if they are having trouble getting it in you need to do something to correct that NOW.
18G
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I gotta admit I am surprised to see the reluctance to use CPAP with obstructive pulmonary disease. Many think that with asthma the CPAP will just compound the air trapping and positive intrathoracic pressures but this is not true.
An asthma patient with moderate to severe exacerbation will develop increased chest pressure... this is where CPAP comes in and works. If you think of the basis mechanics of breathing and pressure gradients its not hard to understand the role of CPAP in asthma (or COPD).
These asthma patients need to overcome (ie create an even high pressure) the increased positive pressure before any airflow will occur. This takes massive amounts of energy, accessory muscle usage, and increases overall work of breathing dramatically. CPAP takes the workload off the patient by creating this higher pressure for the patient thus eliminating energy expenditure, rate of oxygen consumption, reduces accessory muscle usage, and reduces work of breathing. And CPAP allows greater (deeper) delivery of nebulized medications.
CPAP IS RECOMMENDED for asthma and COPD exacerbations and should be used without hesitation with a critical asthma patient.
Our options are to try CPAP or allow the kid to continue to deteriorate to the point of respiratiry failure and then intubate... the second is not the best choice. Trying to have an asthma patient ventilate through a straw is not good!
Our protocols are written with CPAP to be used in asthma and COPD. Even before Epi for asthma.
CPAP is the best choice!
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Medical control strikes again, you have to ring up and ask for adrenaline? ... *Brown shakes his head sadly
Brown would start an adrenaline drip, administer some IV corticosteriods and mix up ketamine in a bag of D5 because she is going to be anaesthetised and intubated.
Brown would start an adrenaline drip, administer some IV corticosteriods and mix up ketamine in a bag of D5 because she is going to be anaesthetised and intubated.
I can't disagree with the analysis of any of the data, but anecdotally I've heard some pretty strong support for the use of BiPAP/CPAP for use in asthma. Personally I would have thought that CPAP was worth a try in this case, and I'll admit some confusion on the issue.
Anecdote is pretty weak however, and unfortunately it may be pretty difficult to conduct a large prospective, randomized, ED/EMS based trial of this issue. It has been tried, but the trial failed due to non-compliance:
http://www.ncbi.nlm.nih.gov/pubmed/11733289
This was an attempt to conduct such a study, with an n goal of about 670. After 35 patients the trial halted, due to reluctance (on the part of both patient and physicians) to allow asthmatics to be enrolled in a study which might possibly deny them BiPAP.
The paper was written up more as an analysis of a attempt to use statistical methods (that I don't pretend to understand ) to eke out some useful information by using calculations that include the pre-study probability of treatment success according to the providers in the study.
The value (or lack thereof) of this data in demonstrating a befit for BiPAP aside, they found that, according to their fancy Bayesian calculations, in order for the small amount of data actually collected to demonstrate a benefit to BiPAP treatment that was "convincing at the 95% confidence level," physicians would have to have had a 98.9% "prior conviction of BiPAP as a successful treatment modality." Yet there was a revolt against allowing patients to be enrolled in the control group, suggesting that the prior conviction may have been pretty close to that number.
In other words, these physicians were probably very sure that BiPAP would be successful prior to their patients being enrolled in the study. Given this, think it's understandable that in the EMS world there would be some confusion over whether PAP may be beneficial in severe asthma, since there are obviously some groups of physicians (One of whom I bet was a EMS medical director) that are obviously very sold on the treatment, some physicians that may disagree, some faceless (but very smart) posters on a website saying no go, and no real clinical data other than small (but leaning positive) reports.
I think the question raised is this: is it true that large peer reviewed studies are the only type of valid clinical data to be used when making a treatment decision?
Granted expert opinion and anecdote are the weakest form of evidence, but what do we do when there is no good data from large prospective trials (especially if there may never be such data, as in rare conditions or cases like this where there is provider resistance to even conducting a trial)? Is "weakest form of evidence" the same as "no evidence?"
Might it be reasonable to try an "unproven" therapy in an emergent situation when there is a lack of data, rather thane evidence of harm? Does this change with the likelihood that the clinical question will ever be answered?
I honestly don't know for sure, although I'd be inclined to lean towards the "give it a trial" side, given that it's impossible to provide good evidence for every possible treatment decision, clinical presentation, or individual patient.
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Status asthmaticus patients do respond well to use of CPAP to re recruit alveoli. It was common practice on the peds critical care team I used to work for. If you can get past the short time of them fighting it, they begin to oxygenate better, more alveoli means better gas exchange, and as they get less hypoxic you will see them become more reasonable.
One of the worst things we can do long term for asthma patients (especially peds) and COPDers is intubation. Intubation turns increases the admit time of these patients considerably.
We used to get so frustrated with adult ERs intubating peds asthma patients without a second thought. I don't like to Monday morning QB another provider's clinical care, but intubation should be the last last option.
Also, steroid treatment shouldn't be overlooked if practical. It won't make much difference in the field, but the results can be seen within a few hours, so the sooner the better.
I tend to agree with most everyone here, mag would have been a good choice, but it seems in this case everything worked out well. Kudos for considering in line nebs. A lot of providers overlook in line nebs, because they lose sight of the primary problem (bronchspasm and constriction) after they've taken over the patient's airway.
One of the worst things we can do long term for asthma patients (especially peds) and COPDers is intubation. Intubation turns increases the admit time of these patients considerably.
We used to get so frustrated with adult ERs intubating peds asthma patients without a second thought. I don't like to Monday morning QB another provider's clinical care, but intubation should be the last last option.
Also, steroid treatment shouldn't be overlooked if practical. It won't make much difference in the field, but the results can be seen within a few hours, so the sooner the better.
I tend to agree with most everyone here, mag would have been a good choice, but it seems in this case everything worked out well. Kudos for considering in line nebs. A lot of providers overlook in line nebs, because they lose sight of the primary problem (bronchspasm and constriction) after they've taken over the patient's airway.
Yes for some reason our peds protocol does not allow offline administration of epi. I am in the process of getting info together and approaching our docs with a change to the protocol. Our adult protocol has epi as an offline option as well as mag. Basically Albuterol/Atrovent, Cpap/BVM both with inline neb'd meds, Epi, Mag. Our Peds read alb/atr, patch for mag. No mention of epi at all unfourtunately, we had to make a judgement call and the dr. agreed with us anyhow. Hopefully we can get the chasnge made.
In our croup/stridor protocol we can give neb'd epi 3mg/5cc saline under 4, and 5mg/3cc saline over 4 years old.
We also do not have ketamine at all. Sadly our choice is to wait until unc. to intubate or try and sedate enough with versed to facilitate intubation.
I would give her the mag, epi, and steroids undoubtably.
But it is not a standard practice and the effects are somewhat variable. It is not worth diverting to a different hospital or doctor shopping.
There are 2 mechanisms by which mag acts. One is to reduce the function of T cells, the other as a smooth muscle relaxor.
If the airway has already reached a critical level of imflammatory response, the mag is unlikely to help acutely.
I would attempt an IM Epi, and if it worked, perhaps follow it up with a nebulized one.
A couple things to consider is if this patient has ever been intubated for asthma prior, and if the duoneb is not helping, there exists the possibility of an infection rather than a hyperimmune response.
18G
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Our protocols regarding epi are kinda strange... for anaphylaxis we don't need to call but for asthma/COPD we do. Guess maybe they don't want providers gunning for the epi until they have tried nebs and CPAP. But if the patient is already in extremis with no air exchange for the nebs to get where they need to be you may need to go straight to epi. Not sure what the rationale is for this.
Aidey
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Just to point out a potential issue, how many people carry a pediatric CPAP mask? We have a 1 size first most set up, and I highly doubt it would seal on an 8yo.
Epi first line medication, IM for us, and swap the child over to our meds/neb at 8LPM. Establish IV, start mag infusion. When practical, administer methylprednisolone and small fluid bolus. Have a BVM and advanced airway equipment nearby. If the kiddo starts to decomp, BVM with neb attached...followed by intubation if needed.
Smash
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I know what you are saying: Lack of evidence is not evidence of lacking. I agree with you on that, and I also agree that we need not necessarily be a slave to statistics, but to use our clinical judgement to identify and treat problems as we find them, pertaining to a specific patient in a specific setting.
The trouble I have with this in this particular setting is that there is potential for harm to come from trying the unproven treatment in the field. With all due respect to all the posters here, I would be a lot more comfortable deferring to a physicians gestalt than a paramedics (mine included) in trying out new things on sick patients (and that's not something most of them do).
Personally I have not seen that many sick asthmatics in the last year or so, only had to intubate 4 in the last 3 months, 3 respiratory arrested and one cardiac arrested, and had a dozen or so in the same time frame who were "sick". It may just be my lack of confidence, but that doesn't make me feel comfortable stepping outside the normal standard of care to try something new and unproven.
There is also a large difference between a physician using BiPAP or PAV in an ED/ICU setting as compared to a paramedic with a WhisperFlow or Boussignac device slapping it on in the back of an abulance.
I may be wrong about CPAP for acute asthma, but if so I am wrong within the bounds of currently accepted knowledge, standards and clinical practice. I would much rather this than be wrong when stepping outside those parameters.
I think that the clinical question will be answered eventually, notwithstanding the issues in gathering data. We may not ever get the big NEXUS sized killer study to answer it, but with a larger number of smaller but methodologically sound RCTs we may be able to paint a clearer picture in the future.
Recommended by whom? Certainly not the British Thoracic Society nor the American Thoracic Society outside of clinical trials.
Given the lack of evidence and the potential for harm it is somewhat reckless to suggest that an unproven treatment should be used "without hesitation". Unless you can back this up with some science?
It may be the choice of your medical director, but "best" is a very relative term.
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If you're carrying CPAP or a BiPAP machine on your unit, why not push to also carry a heliox or a tri-mix breathing gas for use in bronchospasm/status asthmaticus patients? (cost of the gas notwithstanding)
18G
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Smash... our protocols are state-wide medical protocols which are pretty aggressive and science based. They are not created off of a single person's belief. Based on currently available data CPAP is being shown to be effective in the obstructive pulmonary group of patients. The physiology of why CPAP would be beneficial makes sense to me.
I am all for research based EMS... I want validity for what we do. But at the same time people are going way overboard with touting what can be done or should be done based on this study or that study.
Who said were experimenting? CPAP for asthma has been studied if even only small scale, the data supports it, and anecdotally it works very well in a lot of cases. The suggestion of letting people progress to respiratory failure before deciding to act solely because we have no multiple, large, double-blind trials is crazy.
I would much rather try CPAP than wait to intubate an asthma patient any day. There is enough resistance to airflow already so now lets place a straw in their throat for em to breathe through with overzealous providers who don't control the ventilation rate or allow extra time for exhalation... now we have extreme breath stacking and lots of increased pressure in the chest... yeah that makes sense.
Yeah, relative to intubation it is the best modality to try first.
I am all for research based EMS... I want validity for what we do. But at the same time people are going way overboard with touting what can be done or should be done based on this study or that study.
Who said were experimenting? CPAP for asthma has been studied if even only small scale, the data supports it, and anecdotally it works very well in a lot of cases. The suggestion of letting people progress to respiratory failure before deciding to act solely because we have no multiple, large, double-blind trials is crazy.
I would much rather try CPAP than wait to intubate an asthma patient any day. There is enough resistance to airflow already so now lets place a straw in their throat for em to breathe through with overzealous providers who don't control the ventilation rate or allow extra time for exhalation... now we have extreme breath stacking and lots of increased pressure in the chest... yeah that makes sense.
Yeah, relative to intubation it is the best modality to try first.
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18G
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... and call it experimenting or whatever you want, but its what we do in the field that creates much of the data for these later, large scale studies to validate the effectiveness of what we do.