STUDY OBJECTIVES: The precise anatomic sites contributing to exhaled @entity842 (eNO) are still unknown. The present study was designed to analyze profiles of eNO by referring to the He exhalation curve and examining the effects of breath-holding and expiratory flow rates on eNO. @entity1 : Healthy volunteers and @entity1 with stable @entity565 . MEASUREMENTS AND RESULTS We used the He bolus method of the closing volume, and simultaneously analyzed the concentrations of exhaled He and @entity842 (NO). By referring to the He exhalation curve, the expired gas was divided into three parts: airway dead space (phase 1), a mixture of airway and @entity133 (phase 2), and @entity133 (phase 3 and phase 4). The eNO profiles showed a peak in phase 2 (peak eNO) and decreased gradually to a plateau in the latter half of phase 3 (plateau eNO). The levels of peak eNO were higher than those of plateau eNO in both normal subjects and @entity748 @entity1 . Breath-holding increased levels of peak eNO 2.5-fold in both normal subjects and @entity748 @entity1 , but it did not affect the levels of plateau eNO. The levels of peak eNO increased as the expiratory flow rate decreased, and the levels of plateau eNO showed a similar flow dependency. CONCLUSION: A peak value of eNO concentration profiles may directly express the production of NO in the airway.

Analysis of exhaled XXXX by the helium bolus method.

@entity1 :: ('9606', 'Species') :: ['patients', 'PARTICIPANTS'] @entity748 :: ('MESH:D013224', 'Disease') :: ['asthmatic'] @entity565 :: ('MESH:D001249', 'Disease') :: ['asthma'] @entity133 :: ('MESH:D002282', 'Disease') :: ['alveolar gas'] @entity842 :: ('MESH:D009569', 'Chemical') :: ['nitric oxide']
@entity842 :: (MESH:D009569,Chemical) :: ['nitric oxide']
