Suboptimal Peak Inspiratory Flow in Patients Hospitalized for COPD Exacerbation: Prevalence and Predictive Factors

Introduction: Despite the importance of an adequate peak inspiratory flow (PIF) during inhaled therapy in patients with COPD, the available evidence in patients with severe exacerbations and their evolution after admission is limited. We conducted this study to evaluate the PIF during an exacerbation, its variability, and predictors of suboptimal PIF. Material and Methods: A prospective study that included patients admitted for COPD exacerbation. Clinical, demographic, and functional variables were recorded. Using the In-Check DIAL G16^®, PIF without resistance (PIF-nr) and that obtained by simulating the resistance of the patients' usual inhalers (PIF) were determined within the first 48 hours of admission and prior to discharge; also assessed during a stable phase in a subgroup of patients. The results were compared and, through a multivariate study, the factors related to a suboptimal PIF were analyzed. Results: A total of 137 patients were included; 27% were women and the mean age was 69.4 ± 9.8 years. Moreover, 30.8% of the participants with dry powder inhalers had a suboptimal PIF at admission and it was independently associated with female sex (odds ratio [OR] = 8.635; 95% confidence interval [CI] [2.007, 37.152]; p < 0.01) and forced expiratory volume in the 1st second (FEV1) (OR = 0.997; 95% CI: [0.995, 0.999]; p = 0.04). At discharge, suboptimal PIF reduced to 17% (p < 0.01). PIF-nr increased from the time of admission to the stable phase. Conclusion: One third of COPD patients admitted with a severe exacerbation had a suboptimal PIF, being female sex and lower FEV1 independent predictors. PIF-nr improved progressively after the exacerbation.