Objectives: Correct use of inhaler devices is critical in ensuring the
optimal lung bioavailability of the inhaled drug. The study aimed to
assess inhaler technique used in patients with using metered-dose
inhalers (MDI) by correlating with urinary salbutamol excretion post
inhalation and its correlation with disease control. Methods: Thirty
patients with obstructive pulmonary diseases attending outpatients’
services inhaled two doses of salbutamol 100 µg and urine samples were
collected after 30 min. Inhaler technique scores were assessed using a
standardized 8-point checklist. The 30-minute concentration of urinary
salbutamol is then correlated with inhaler technique scores and control
status of the disease. Key findings: The mean age of the subjects was
60.8 (SD ± 9.338). The mean (SD) 30 min urinary salbutamol concentration
was 3.6±1.6 µg/ml. The mean concentration of salbutamol was found to be
2.3 µg/ml (n=1), 2.3 µg/ml (n=5), 3.1 µg/ml (n=7), 3.9 µg/ml (n=8), 4.7
µg/ml (n=5), 5.3 µg/ml (n=3), and 5.0 µg/ml (n=1) among patients
performing 1, 2, 3, 4, 5, 6, 7, 8 steps correctly, respectively. There
was a statistically significant correlation (p=0.028) witnessed between
the mean 30 min urinary salbutamol concentration and total correct
steps. The frequency of exacerbation, use of antibiotics, and oral
corticosteroids (OCS) were more in patients with poor inhaler technique
scores, although statistical significance was achieved only for
frequency of antibiotics use (p=0.032). Conclusions: The 30 min
salbutamol urinary concentration evaluation may help to identify
patients who were underdosed due to poor handling of inhaler devices.
Being a complex procedure, it can at least be initiated in patients
reporting frequent exacerbations, hospitalization, and those who need
multiple drugs for disease control.
Urinary Excretion Post Inhalation Method to Correlate Inhaler Technique with Disease Control in Patients with Obstructive Pulmonary Diseases Using Own Metered Dose Inhaler (MDI)
