Use of pulmonary function testing to predict successful inhaler device technique.
Kelly BA, and Martitosov A. Use of pulmonary function testing to predict successful inhaler device technique. Am J Respir Crit Care Med 2018; 197
Am J Respir Crit Care Med
Inhaler based medications remain a cornerstone of treatment for obstructive lung disease, however, errors in inhaler technique attributable to modifiable and non-modifiable issues have remained unacceptably high. A previous study in our clinic demonstrated that the Vitalograph Aerosol Inhalation Monitor (AIM) was an effective tool for optimizing inhaler regimens based on patient technique. The purpose of this study is to determine if pulmonary function testing (PFT) parameters can predict success or failure of inhaler technique in patients with chronic obstructive pulmonary disease (COPD), asthma or asthma COPD overlap syndrome. Methods This retrospective cohort analysis included patients seen in the outpatient pulmonary clinic at Henry Ford Hospital in Detroit, Michigan from October 2015 to March 2017. Patients were included if they had a diagnosis of COPD, Asthma or Asthma COPD Overlap Syndrome, spoke English, and were 18 years of age or older. Patients were excluded if they had a tracheostomy or had a diagnosis of interstitial lung disease, sarcoidosis, or lung cancer. Inhaler technique, based on AIM testing, and baseline PFT data were analyzed. The primary endpoint was the correlation of successful dry powder inhaler (DPI) device technique with actual to predicted ratio of inspiratory vital capacity (IVC) using logistic regression with device technique pass/fail as the outcome variable. Results 119 patients were included in the initial analysis. The majority of patients were female (62.2%) with a diagnosis of COPD or ACOS (73.9%) and a median age of 63 years. The median IVC was 67.5% and the predicted ratio was 90. DPI had an overall failure rate of 83% with inhalation time being the greatest predictor of failure (79.8%). The ratio of actual to predicted IVC predicted pass/failure of DPI technique in the elements of Inhalation Time (p=0.0414, OR 0.97, R2 0.0409), Breath Hold Time (p=0.003, OR 0.958, R2 0.801) and overall success (p=0.0387, OR 0.073, R2 0.0461). Conclusion This pilot study reveals statistically significant correlation between PFT variables readily available to the clinical Pulmonologist, and probability of successful inhaler device technique. A prospective trial is underway to collect additional data to develop a model with sensitive cut-points that will help guide choice of inhaler with the best chance of successful device usage.