Nitric oxide Analyzer
In the present study, to further characterize the peak eNO, we used the He bolus method of closing volume, in which the He exhalation profile divides the expired gas into a mixture of dead space and airway (phase 1), a mixture of airway and alveolar gas (phase 2), and alveolar gas (phase 3 and phase 4), and analyzed profiles of eNO by referring to the He exhalation curve. We also studied the effects of breath-holding and expiratory flow rates on eNO in normal subjects and asthmatic patients.
Patients with bronchial asthma (age range, 22 to 75 years) were enrolled at our outpatient clinic, and healthy volunteers (age range, 23 to 46 years) were also recruited from hospital employees. Patients with asthma were all in stable condition, and its severity was mild to moderate (Table 1) read more generic claritin. All patients and subjects were nonsmokers. Written informed consent was obtained from all participants.
Measurement of eNO
eNO was measured according to the method of Silkoff et al. Levels of eNO were measured by a rapid-response chemilumi-nescence analyzer (NOA 270B; Sievers; Boulder, CO), and a calibration was performed between 520 parts per billion (ppb) and 0 ppb. The linearity of the analyzer response was verified by repeated calibrations. The apparatus of eNO measurement consists of a one-way valve (model 1400; Hans-Rudolph; Kansas City, MO), of which the inspiratory port is connected to a Douglas bag containing NO-free air, and of which the expiratory port is connected to a pneumotachograph and a spring-loaded valve (Threshold PEP; Healthscan Products; Cedar Grove, NJ) to give a constant positive pressure (14 cm H2O) in relation to the expiratory line. eNO was continuously sampled via the side port close to the mouth at a sample flow of 200 mL/min. The airway pressure was continuously monitored with a pressure transducer (Validyne MP-45; Validyne Engineering; Northridge, CA) connected to a tap of the mouthpiece. In addition...
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