Vmax229d

Participants underwent a ramp incremental CPET on an electromagnetically braked cycle ergometer (Ergoline 800; Sensor Medics, Anaheim, CA, United States), before and after completion of the program. Individualized workload increments were estimated according to the equation of Hansen et al[20 (link)]. Gas exchange was measured with the patient breathing through a low resistance valve, with the nose clamped, using an ergospirometry system (Vmax229D; Sensor Medics) calibrated with a known gas mixture before each test. Respiratory indicators (breath-by-breath oxygen uptake [VO₂], carbon dioxide output [VCO₂] and ventilation [V_E]) were measured. Peripheral O₂ saturation was monitored continuously by pulse oximetry. Heart rate and rhythm were monitored by a MAX 1, 12-lead electrocardiographic system (Marquette Electronics, Milwaukee, WI, United States) and blood pressure was measured every 2 min with a mercury sphygmomanometer. All patients were verbally encouraged to exercise to intolerable leg fatigue or dyspnea. CPET variables employed in the study were VO_2peak and peak workload (W_peak). VO_2peak was determined as the average value of VO₂ data measured at the final 20-s period of the exercise phase, and W_peak as the corresponding work rate[20 (link)].

Spirometry was performed using a Vmax 22 instrument (Sensor-Medics; Yorba Linda, CA, USA) or a PFDX machine (MedGraphics, St Paul, MN, USA), as recommended by the American Thoracic Society/European Respiratory Society.12 FVC, FEV₁, and FEV₁/FVC were evaluated both before and 15 min after inhalation of 400 μg albuterol. Lung volume was measured by body plethysmography (V600, Sensor-Medics, or PFDX). DL_CO was assessed by the single-breath method using a Vmax229D (Sensor-Medics) or a Masterlab Body (Jaeger AB, Wurtsburg, Germany) instrument. Absolute values of FVC and FEV₁ were obtained, and the percentage of the predicted value (% predicted) for FEV₁ and FVC was calculated from equations formulated using data from a population of healthy non-smoking Koreans.13 Spirometry was conducted at baseline and after 12 weeks of treatment.

The method for pulmonary function tests have been described previously5 . Spirometry was performed by using a Vmax 22 (Sensor-Medics, Yorba Linda, CA, USA) or a PFDX (MedGraphics, St Paul, MN, USA). To assess post-bronchodilator FEV₁ increases, spirometry was performed before bronchodilation and 15 minutes after inhalation of salbutamol 400 µg through a metered-dose inhaler with a spacer. Bronchodilator reversibility was evaluated by measuring post-bronchodilator FEV₁ increase in liters. Lung volumes were measured by body plethysmography (V6200; Sensor-Medics or PFDX). Diffusing capacity for carbon monoxide (DLco) was measured by the single-breath method using a Vmax229D (Sensor-Medics) or a Masterlab Body (JaegerAB, Würtsburg, Germany). All pulmonary function tests were performed as recommended by the American Thoracic Society (ATS)/European Respiratory Society (ERS).