Visual feedback using electrical impedance tomography during inhalation therapy for chronic obstructive lung disease: a pilot study

Abstract Airflow limitation and hyperinflation contribute to increased respiratory workload and dyspnea in COPD. Inhalation therapy plays a crucial role, but its effectiveness depends on correct technique. Electrical impedance tomography (EIT) offers real-time visualization of ventilation and may improve inhalation technique, when used as visual feedback. This study aimed to investigate the impact of feedback-guided inhalation using EIT on lung function, specifically targeting obstructive and hyperinflation parameters. In this prospective, randomized, single-blinded study, 29 patients with COPD were divided into a control group (no feedback) and an intervention group (inhalation using visual feedback). Body plethysmography was performed before and after a single inhalation session. The primary outcome was the change in lung function parameters. Secondary outcomes included real-time EIT data during inhalation and a follow-up questionnaire assessing subjective benefit. No differences were observed in obstructive lung parameters (FEV1) between groups, but the intervention group showed a significant FRC reduction compared to the control group (control − 0.1 L vs. intervention − 0.4 L, p < 0.05). Resistance indices (sRtot/sReff) tended to increase in the intervention group whereas a decrease was noted in control. No in between differences in EIT-derived data or subjective benefit at follow-up. Visual feedback using lung EIT may improve inhalation technique and breathing mechanics, which may contribute to reduced hyperinflation. However, changes in breathing pattern may also explain changes in lung parameters, highlighting the complex lung volume, ventilation and airway resistance interplay. Future research should investigate repeated EIT-feedback effects on lung function and disease symptoms. Trial registration : Registered at: DRKS.de; Clinical Trial Registration Number: DRKS-IDDRKS00037626; Registration Date: 11.08.2025.