Lung function measured by impulse oscillometry and spirometry following eucapnic voluntary hyperventilation: METHODS (2)

Airway resistance and X were determined by IOS (MS-IOS, Jaeger, Germany) using the manufacturer’s recommended techniques. Real-time recordings of mouth pressure and flow signals pulsed through the 5 Hz to 35 Hz spectrum were superimposed and displayed on a computer screen. Fast fourier transformation analysis calculated R5 (cm ^O/lps [litres per second]), X (cm ^O/lps), Fres (Hz) and AX (cm H2O/L).
Pulmonary function response to EVH was determined using spirometry immediately following the IOS manoeuvre. Forced vital capacity (FVC), FEVp FEVj to FVC ratio, and FEF through the middle portion of the vital capacity (FEF25^) were measured pre- and post-EVH. The procedure for all pulmonary function tests involved the following steps: three normal tidal volume breaths; maximal inhalation; forced maximal exhalation; and maximal inhalation as previously performed. All testing was completed using a calibrated, computerized pneumotachograph spirometer (Masterscope PC, Jaeger, Germany). Baseline pulmonary function was established by selecting the best of three resting pulmonary function tests. An individual measurement of maximum voluntary ventilation was obtained using a 12 s manoeuvre. Postchallenge pulmonary function was measured at 5 min, 10 min and 15 min after a challenge. If any postchallenge time point measurement was technically unacceptable, it was repeated. buy ampicillin
Descriptive statistics for resting lung function were calculated for IOS and spirometry lung function measurements. Repeated measures ANOVA was used to analyze differences between post-EVH lung function measurements and between AHR+ and AHR-groups. Pearson Product Moment correlations were used to evaluate relationships between resting measurements and between postchallenge falls in FEVj, airway resistance and X measurements (determined using IOS). P<0.05 was considered significant.

Category: Lung function

Tags: Airway hyperresponsiveness, Dry air, Eucapnic voluntary hyperpnea, Exercise-induced bronchoconstriction, Forced oscillation