Okay, yes, I'm going against the general consensus of doctors and nurses where I work, but IT IS TRUE.
Consider this. You put 0.5cc Ventolin into a nebulizer. You give the breathing treatment with a mouthpiece and a wide bore connector tubing conected to the other end to act as a reservoir to store some of the "wasted" medicine during exhalation.
Approximately a half of that 0.5cc dose is wasted just on passive exhalation while the treatment is going. About half of what is inhaled impacts in the mouth, the back of the throat and the large airways. The rest, the particles that are 0.2-0.5 microns, actually make it to the lungs.
So, in essense, of the original 0.5cc, about a quarter of it actually makes it to the bronchioles to conect to beta 2 cells and cause bronchodilation.
So, imagine if you are simply blowing the mist by the patient's face. That's right, you are wasting even more medicine. I would imagine, if studies were done, less than 10% of the medicine gets to where it's supposed to go -- the bronchioles.
Add to that if the patient is crying, and you waste even more.
Now you have a doctor who thinks that since a 0.5cc dose is the adult dose, he should give half of that, so he orders neb treatment by blowby 0.25cc Ventolin. So that is even less med to the bronchioles.
In essense, it has been proven that blowby treatments are useless. And when they are given you should probably give twice the dose, not half.
Add to this the fact that Ventolin hasn't even been proven effective on the small lungs of infants. They don't even know if it works. I wrote about this before.
Still, 0.25cc Ventolin is usually the given dose. A blowby is usually given, and the treatment is ordered every four hours.
If you don't believe me, check out this link to original article in the August 2008 issue of RT Magazine. The article is aptly titled, "Kids and Asthma: Making (and Teaching) the Right Choices." The author is Bill Pruitt, RRT, AE-C, CPFT.
Or Read this excerpt from the article:
The technique of directing the nebulizer output toward the patient's nose and mouth (referred to as "blow-by") is considered to be inappropriate and should not be used. The AARC CPG on aerosol delivery devices recommends that a nebulizer with a mouthpiece and an extension reservoir be used in children >3 years of age if they are cooperative, are spontaneously breathing, and do not have an artificial airway in place.Keep in mind sometimes you have no choice but to give a blowby. This is fine so long as that "blowby" isn't considered by the doctor to be the leading cause of treatment for that child.
Consider this RT Cave Rule #31