Peak Inspiratory Flow in COPD Patients Treated with Pressurized Metered-Dose Inhalers and Spacers: Implications for Inhaler Selection. A Multicenter Cross-Sectional Study.

Background: Spacer devices are frequently prescribed with pressurized metered-dose inhalers (pMDIs) in patients with COPD for a variety of clinical and practical reasons, including concerns about inspiratory capacity, inhaler technique, and hand-breath coordination. However, inspiratory flow is rarely measured objectively. Purpose: To determine whether COPD patients treated with pMDIs and spacers can generate adequate peak inspiratory flow (PIF) for dry powder inhaler (DPI) use, to evaluate the impact of incomplete exhalation, and to examine patient perceptions of spacer use. Patients and Methods: This multicenter, cross-sectional study included 273 clinically stable COPD patients treated with pMDIs and spacers across 70 Spanish centers. PIF was measured with the In-Check Dial at medium-low (R2) and medium-high (R4) resistance under both standard and suboptimal conditions. Patient knowledge, satisfaction, and perceived barriers were evaluated using structured study questionnaires. Results: Overall, 96.0% of patients achieved a PIF ≥30 L/min at R4, whereas 61.9% reached ≥60 L/min. Incomplete exhalation had only a limited effect on inspiratory performance, with 94.1% of patients maintaining a PIF ≥30 L/min at R4. Lower PIF was associated with greater dyspnea and more severe airflow limitation in bivariate analyses. Spacer prescription was seldom based on objective PIF assessment. Most patients reported practical limitations associated with spacer use and expressed a preference for simpler inhaler devices. Conclusion: Most COPD patients treated with pMDIs and spacers appear to have sufficient inspiratory capacity to use medium- to high-resistance DPIs. Routine objective assessment of PIF may help optimize individualized inhaler selection and identify patients who could benefit from alternative inhaler devices.