Assessment of exhaled nitric oxide kinetics in healthy infants.
Exhaled nitric oxide (Fe(NO)) measurements provide a noninvasive approach to the evaluation of airway inflammation. Flow-independent NO exchange parameters [airway NO transfer factor (D(NO)) and airway wall NO concentration (Cw(NO))] can be estimated from Fe(NO) measurements at low flows and may elucidate mechanisms of disturbances in NO exchange. We measured Fe(NO) in sedated infants by using an adaptation of a raised lung volume rapid thoracic compression technique that creates forced expiration through a mass-flow controller that lasts 5-10 s, at a constant preset flow. We measured Fe(NO) at expired flows of 50, 25, and 15 ml/s in five healthy infants (7-31 mo). Median Fe(NO) increased [24, 40, and 60 parts per billion (ppb)] with decreasing expiratory flows (50, 25, and 15 ml/s). Group median (range) for D(NO) and Cw(NO) were 12.7 (3.2-37) x 10(-3) nl. s(-1). ppb(-1) and 108.9 (49-385) ppb, respectively, similar to values reported in healthy adults. Exhaled NO is flow dependent; flow-independent parameters of exhaled NO kinetics can be assessed in infants and are similar to values described in adults.
Martínez
T
T
Department of Pediatric Pulmonology and Critical Care, Indiana University Medical Center, Indianapolis, Indiana 46202, USA.
Weist
A
A
Williams
T
T
Clem
C
C
Silkoff
P
P
Tepper
R S
RS
D001944:Breath Tests / Q000295:instrumentation / Q000379:methods; D002675:Child, Preschool; D004864:Equipment and Supplies; D005260:Female; D005540:Forced Expiratory Flow Rates; D006801:Humans; D007223:Infant; D007700:Kinetics; D008297:Male; D009055:Mouth / Q000502:physiology; D009569:Nitric Oxide; D009994:Osmolar Concentration; D011312:Pressure
D009569:Nitric Oxide