Patients being treated for COPD or asthma are often using inhaler therapy. It is important when using this kind of therapy that the medication gets as deeply into the airways as possible. When adequate drug deposition cannot be accomplished in a given patient, it may appear that the therapy is not effective and, indeed, it is not, but not because of the medication but because it is not getting to the place where it can effectively work.
Obesity is known to be a detrimental factor in the response to inhaled medications. There are at least two factors involved in this impairment to drug deposition. The first may be that the airways of obese patients tend to be of smaller caliber, making them prone to collapse. The second factor is the upper airway characteristics in the obese patients. Obesity is an important consideration in patients requiring inhaler therapy since obese patients have been shown to have 30% less medication reach the lower airways when compared to non-obese patients.
There is a classifications of the upper airway with a funny name called the Mallampatti score. The higher the score that is recorded, the smaller the upper airway. This score is used by anesthesiologists to help determine how easy or difficult it may be to intubate a patient.
Interestingly, when medications were delivered to obese patients with high Mallampatti scores via a nebular device, the deposition was improved and may point the way to help this group of patients deposit more medication into the lungs.