Expiratory and inspiratory resistance and reactance from respiratory oscillometry defining expiratory flow limitation in obstructive lung diseases

• Published in: Clinical physiology and functional imaging Vol. 44; no. 6; pp. 426 - 435
• Main Authors: Nasr, Abir, Papapostolou, Georgia, Jarenbäck, Linnea, Romberg, Kerstin, Tunsäter, Alf, Ankerst, Jaro, Bjermer, Leif, Tufvesson, Ellen
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.11.2024
• Subjects: Adult; Aged; airflow limitation; airway obstruction; Airway Resistance; Asthma; Asthma - diagnosis; Asthma - physiopathology; Case-Control Studies; Chronic obstructive pulmonary disease; Clinical Medicine; COPD; Correlation; Disease resistance; Exhalation; Female; Flow resistance; Forced Expiratory Volume; Humans; Inhalation; Klinisk medicin; Lung - physiopathology; Lung diseases; Lungmedicin och allergi; Male; Medical and Health Sciences; Medicin och hälsovetenskap; Middle Aged; Oscillometry - methods; Plethysmography; Plethysmography, Whole Body - methods; Predictive Value of Tests; Pulmonary Disease, Chronic Obstructive - diagnosis; Pulmonary Disease, Chronic Obstructive - physiopathology; Quality of Life; Reactance; Respiratory Medicine and Allergy; Signs and symptoms; smoker; Smoking; Smoking - adverse effects; Smoking - physiopathology; Spirometry - methods; Surveys and Questionnaires; Trapping; airway obstruction; airflow limitation; smoker; asthma; COPD
• ISSN: 1475-0961; 1475-097X; 1475-097X
• DOI: 10.1111/cpf.12895

Background Expiratory flow limitation (EFL) during tidal breathing and lung hyperinflation have been identified as major decisive factors for disease status, prognosis and response to therapy in obstructive lung diseases. Aim To investigate the delta values between expiratory and inspiratory resistance and reactance, measured using respiratory oscillometry and its correlation with air trapping and symptoms in subjects with obstructive lung diseases. Methods Four hundred and seventy‐one subjects (96 with chronic obstructive pulmonary disease [COPD], 311 with asthma, 30 healthy smokers and 34 healthy subjects) were included. Spirometry, body plethysmography and respiratory oscillometry measurements were performed and the differences between the expiratory and inspiratory respiratory oscillometry values (as delta values) were calculated. Questionnaires regarding symptoms and quality of life were administered. Results Patients with COPD and healthy smokers had an increased delta resistance at 5 Hz (R5) compared with patients with asthma (p < 0.0001 and p = 0.037, respectively) and healthy subjects (p = 0.0004 and p = 0.012, respectively). Patients with COPD also had higher values of ΔR5–R19 than healthy subjects (p = 0.0001) and patients with asthma (p < 0.0001). Delta reactance at 5 Hz (X5) was significantly more impaired in COPD patients than in asthma and healthy subjects (p < 0.0001 for all). There was a correlation between the ratio of residual volume and total lung capacity and ΔR5 (p = 0.0047; r = 0.32), ΔR5–R19 (p = 0.0002; r = 0.41) and ΔX5 (p < 0.0001; r = −0.44), for all subjects. ΔX5 correlated with symptoms in COPD, healthy smokers and patients with asthma. In addition, ΔR5 correlated with asthma symptoms. Conclusion EFL was most prominent in parameters measuring peripheral resistance and reactance and correlated with air trapping and airway symptoms.