Bronchiolitis: The Rationale Behind the New AAP Guideline

Ricardo A. Quinonez, MD; Shawn L. Ralston, MD


November 13, 2014

That said, I would like to reiterate that guidelines don't tell you what to do in the case of every patient. Guidelines serve as an evidence-based shared baseline. Those who concluded that this guideline means you can never use a bronchodilator in a patient with bronchiolitis are misunderstanding the utility of guidelines. The vast majority of patients with bronchiolitis do not benefit from bronchodilators, but that does not mean that the occasional patient might not. The problem is, if we apply this across the board to all of the patients we are evaluating and treating for first-time wheezing, we're doing more harm than good. Ultimately I think the evidence supports the current recommendation, and it would be nearly impossible to craft an evidence-based recommendation to use albuterol in very young children with viral wheezing.

Dr Quinonez: It seems to me that another potential harm of bronchodilators, which wasn't discussed in the guidelines, is that, at least in the setting of asthma, they can cause significant ventilation/perfusion (VQ) mismatches. A patient who wasn't hypoxic now exhibits an artificially created hypoxia and may end up being admitted as a result.

Dr Ralston: I think that that is something that hospitalists in particular have a very strong belief about, based on our clinical practice. There's only a single, very small study by Ho and colleagues[3] addressing that issue, and this study did not show a profound impact, though it did show desaturations after albuterol. However, the researchers probably weren't studying the same dose that we're using in our emergency rooms at this point. It's not unusual for us to admit a patient who's received three back-to-back rounds of albuterol at doses of 2.5-5 mg each. I do think that it is a significant harm. I think that we are prisoners of the pulse ox and that the reason the vast majority of patients get admitted to the hospital with bronchiolitis is simply because of a borderline reading on oximetry. However, there isn't a strong evidence basis to support this particular personal opinion. We didn't feel like we could report this as a potential harm in the guideline, which is, again, an evidence-based document.

There is certainly some distress in the emergency department (ED) community with the idea that they've been doing trials of albuterol, and that some of these patients are getting benefit and they're keeping those patients out of the hospital. Again, that's their belief, based on their clinical experience and not an evidence-based assertion. Of course, our belief is that an equal number of patients are being unnecessarily admitted to the hospital for transient hypoxia. So, I think there is still quite a bit of discrepancy between the available evidence base and our own clinical experience and biases. We'll see how that all plays out.

Dr Quinonez: The use of continuous pulse oximetry in particular is discouraged now in this new guideline, another recommendation that may be difficult for some clinicians. Again, could you tell us why, and what is the potential harm?

Dr Ralston: This was also an area where there is paucity of evidence upon which to base recommendations. It's interesting to me that we adopted this technology wholeheartedly before asking many questions about it. The assumptions were that this was going to be beneficial. Indeed, it sure beats the heck out of doing an arterial blood gas and is a wonderful technology. However, we never considered what applying pulse oximetry across an entire population of patients was going to do. I think it's very clear from the epidemiology that what it did was cause a huge number of patients to be admitted to the hospital who were not being admitted prior to the advent of the technology. We suddenly started paying attention to the machine and not to the rest of the patient. I think there's a small amount of literature that supports that, but there's also a common-sense look at what has happened. The rate of hospitalization did increase dramatically at the time of universal pulse oximetry usage: 150%. There was no diagnostic reassignment and no sudden increase in mortality or severity of illness, so it's probably fair to blame the pulse oximeter. The short duration of most hospitalizations for bronchiolitis indicates that the majority are for mild to moderate disease. Our typical hospital stay in the United States is 2-3 days. Bronchiolitis itself was not getting worse but we were hospitalizing more children. That is a hard argument to refute, based on the epidemiology, and I think pulse oximetry is to blame for it.


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