So, what is MDI pump priming? It's when you waste 1-4 puffs of the medicine so that when you take it for real you are getting the maximum medicine available.
According to the American Associacion for Respiratory Care's "Guide to Aerosol Dellivery Devices," the following are the recommended Priming Requirements for Commercially Available MDIs:
Medication Propellant Time to Prime # of Sprays Albuterols:
- Albuterol* HFA Prior to first use 3 (With 3 days of nonuse 3)
- Levalbuterol HFA Prior to first use 4 (With 3 days of nonuse 4)
- Maxair Autohaler CFC Prior to first use 2 (With 2 days of nonuse 2)
- Azmacort® CFC Prior to first use 2 (With 3 days of nonuse 2)
- Flovent® HFA Prior to first use 4 (With 3 weeks of nonuse 4)
- QVAR® HFA Prior to first use 2 (With 10 days of nonuse 2)
- AeroSpan™ HFA Prior to first use 2 (With > 2 weeks of nonuse 2)
- Atrovent® HFA Prior to first use 2 (With 3 days of nonuse 2)
- Combivent® CFC Prior to first use 3 (With 1 day of nonuse 3)
- Intal® CFC Prior to first use 1
Despite the recommendation that all MDIs be primed before each use, I have never in my life ever done it -- not once.
I have good reason, though, for not doing it. First, when I learned how to use an MDI by my physician in 1980 the practice was never taught. Back then you were taught to place the inhaler two finger lengths from your mouth and squirt.
Second, when I was a kid I was a hardluck asthmatic and a bronchodilatoraholic. That meant that quite often my rescue inhaler (my Alupent back then) lasted me seven days or less, when it was supposed to last 4-6 weeks. So I had to do whatever I could to make the inhaler last longer, and that meant not wasting puffs.
Likewise, as a child asthmatic, I never wanted to bother my mom to run to the pharmacy, so that was another reason to make my inhaler last longer. Yet, even by not priming, my inhaler still only lasted about a week.
Third, I never heard of MDI priming until a few months ago. So after 30 years of not priming the pump, it's going to take me a while get into the habit. This is probably the stubborn me talking, but I really don't see a need to prime. Even if I'm only getting 2% of the medicine when I take my two puffs, that 2% seems to be sufficient. So I really don't see a need to prime the pump.
Yet theres an old saying this reminds me of: We do the best we can with the wisdom we have, and when we learn better we do better. So perhaps it's time to change my ways.As a respiratory therapist, I suppose I'm going to have to add pump-priming to my how-to-use-an-MDI regime.
So, what about you? Did you know about the need to prime the MDI pump? Are you an MDI pump primer? If you're an RT, do you teach this to your patients?
* Note that Proventil and Ventolin HFA have the same priming requirements.