Myths in Medicine - The Nebulizer...Smoke and Mirrors?

Myth:  An individual with an asthma exacerbation should receive bronchodilators via nebulizer in the emergency room (or at home or in the general practitioner's office).

False.  

Metered dose inhalers (MDIs), utilized with a spacer, are at least as effective, if not more effective than nebulized bronchodilators during most asthma exacerbations.  

• This makes sense if you've ever seen someone receiving a "neb" treatment.  The fog is everywhere!  Studies have radiolabeled particles to determine the amount that actually reaches the lung and this amount is much less when nebulized (which is why we give much higher doses for this route of administration...the particles are seeping out of the mask into the curtains, etc).

Limitations:

• Some patients may benefit more from a nebulizer than an MDI; however, these might be the patients who actually need positive pressure ventilation through BiPap or other means.  These patients are often the ones who will end up needing to be admitted and are receiving everything in the arsenal for management of asthma exacerbations (including magnesium).

So, why do people still use nebulizers in this patient population?

• It appears that many patients expect that when they present to the ED with an asthma exacerbation, they will receive a nebulizer.  This is somewhat understandable, particularly if they failed their normal "rescue" inhaler at home.  Additionally, there's the lure of the mysterious fog that pours out of delivery device.  However, the dosing and composition of the MDI will likely be different than the standard 2 puffs of albuterol that the patient may use in the outpatient setting (Check out the Goh study below where patients averaged 10 puffs and were given ipratropium).  

Why else is MDI + spacer a good idea?

• Use in the ED or in the hospital/office setting offers the ability to reinforce this modality as an excellent means of treating asthma exacerbations. 
• Supervised use of MDI + spacer proffers the opportunity to educate patients and families on the proper inhaler technique.  
• Even young kids can actually be quite good with the spacer face mask and this also reinforces to the parents that the child is, indeed capable of using an inhaler.
• Cost-effective
• Takes less time
• Nebulizer machines are often filthy.  While on a pediatric rotation in the rural deep south, I found that nearly every family seemed to have a "breathin' machine" at home or had used one of a friend/family member on their own.  How many do you think had ever been cleaned?

One Snippet of Evidence - The Goh Study

• Methods: Comparison of  hospitalization and re-admission rates between 10,258 cases treated in 2000–2002 and 9,693 cases treated in 2004–2006 for asthma exacerbation in the ED. In 2003, the ED switched from using nebulizers to MDIs. The number of salbutamol puffs in the ER was standardized to 10 puffs for children >10 kg and 5 puffs for children <10 kg, and ipratropium bromide was given routinely to all children. 
• Results:  
• There was no increase in the admission rate to inpatient care (30.3% vs. 31.2%) nor in the admission rate to intensive care (0.21% vs. 0.20%) units. 
• The average length of hospital stay was 2.67 days versus 2.27 days before and after the change, respectively.  
• A significant reduction was seen in the re-admission rate within 72 h after departure to home from the ED following the change (5.2% vs. 3.8%)

Additional References:

-Goh AE, Tang JP, Ling H, et al., Efficacy of metered-dose inhalers for children with acute asthma exacerbations. Pediatr Pulmonol2011; 46: 421–427. DOI: 10.1002/ppul.21384.

-Doan Q, Shefrin A, Johnson D. Cost-effectiveness of meter-dose inhalers for asthma exacerbations in the pediatric emergency department. Pediatrics 2011; 127(5): 1105-1111

-Castro-Rodriguez JA, Rodrigo GJ. beta-agonists through metered-dose inhaler with valved holding chamber versus nebulizer for acute exacerbation of wheezing or asthma in children under 5 years of age: a systematic review with meta-analysis. J Pediatr 2004;145:172–7.

-Dolovich MB, Ahrens RC, Hess DR, Anderson P, Dhand R, Rau JL, Smaldone GC, Guyatt G. Device selection and outcomes of aerosol therapy: evidence-based guidelines: American College of Chest Physicians/American College of Asthma, Allergy, and Immunology. Chest 2005 Jan;127(1):335-71.