title: Interrelationship between postocclusional oscillatory pressure transients and standard lung function in healthy and asthmatic children.
abstract: We studied the correlation between characteristics of the postocclusional oscillatory airway opening pressure transients after flow interruption and body height, the degree of pulmonary hyperinflation [measured by thoracic gas volume (TGV)], and the degree of airway obstruction [measured by airway resistance (Raw)] and maximal expiratory flow at 50% vital capacity (MEF50) in 10 healthy and 50 asthmatic children age 7-16 years. Focusing on the damped oscillatory change in pressure, the first derivative of the shutter curve was analyzed, featuring a natural frequency fO and damping factor d in the time domain, and frequency FFS and power AFS in the frequency domain. A maximal frequency was found at approximately 80 Hz without a two peak distribution as described in dogs. Multiple linear forward step analysis revealed that omega O (the undamped, natural frequency) and AFS were related to body height (P < 0.001). The damping factor d (independent of body height) was related to TGV and MEF50 (P < 0.001), and FFS to Raw (P < 0.001). The analysis of the postocclusional pressure transients after airflow interruption provides information on the resistive, elastic and inertive properties of the thoraco-pulmonary system. The measurements obtained are influenced by the end-expiratory resting level (or the degree of pulmonary hyperinflation) and the degree of airway obstruction.
authors.affiliation: Department of Pediatrics, University of Berne, Inselspital, Switzerland.
authors.forename: U
authors.initials: U
authors.lastname: Frey
authors.forename: R
authors.initials: R
authors.lastname: Kraemer
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000403:Airway Resistance; D001249:Asthma / Q000503:physiopathology*; D001827:Body Height; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D012129:Respiratory Function Tests; D012737:Sex Factors; D013223:Statistics as Topic