@article {Schibler912, author = {A. Schibler and G.L. Hall and F. Businger and B. Reinmann and J.H. Wildhaber and M. Cernelc and U. Frey}, title = {Measurement of lung volume and ventilation distribution with an ultrasonic flow meter in healthy infants}, volume = {20}, number = {4}, pages = {912--918}, year = {2002}, doi = {10.1183/09031936.02.00226002}, publisher = {European Respiratory Society}, abstract = {Small airway disease in infants is characterised by abnormal lung volume and uneven ventilation distribution. An inert tracer gas washin/washout technique using a pulsed ultrasonic flow meter is presented to measure functional residual capacity (FRC) and ventilation distribution in spontaneously breathing and unsedated infants. With a pulsed ultrasound sent through the main stream of the flow meter, flow, volume and MM of the breathing gas can be calculated. Sulphur hexafluoride was used as a tracer gas. In a mechanical lung model (volume range 53{\textendash}188 mL) and in 12 healthy infants (aged 38.3{\textpm}9.2 days; mean{\textpm}sd) accuracy and reproducibility of the technique was assessed. Indices of ventilation distribution such as alveolar-based mean dilution number (AMDN) and pulmonary clearance delay (PCD) were calculated. Mean error of volume measurement in the lung model was 0.58\% (coefficient of variance (CV) 1.3\%). FRC was in the low predicted range for normal infants (18.0{\textpm}2.0 mL{\textperiodcentered}kg-1) and highly reproducible (5.5{\textpm}1.7\% intra-subject CV). AMDN was 1.63{\textpm}0.15 and PCD was 52.9{\textpm}11.1\%. Measurement of functional residual capacity and ventilation distribution using a sulphur hexafluoride washin/washout and an ultrasonic flow meter proved to be highly accurate and reproducible in a lung model and in healthy, spontaneously breathing and unsedated infants. This study was supported by the Swiss National Foundation (SCORE 32-51974.97), Australian National Health and Medical Research Council, Swiss CF Foundation, AstraZeneca (Switzerland)}, issn = {0903-1936}, URL = {https://erj.ersjournals.com/content/20/4/912}, eprint = {https://erj.ersjournals.com/content/20/4/912.full.pdf}, journal = {European Respiratory Journal} }