Lung function measurements in children - copsac
Lung function measurements in children - copsac
Lung function measurements in children - copsac
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Children less than 7 years were tested with dry air hyperventilation as previously<br />
described and validated <strong>in</strong> this age-group (18, 36, 132).<br />
Fractional exhaled nitric oxide<br />
Fractional exhaled nitric oxide (F E NO) was measured by the onl<strong>in</strong>e s<strong>in</strong>gle breath<br />
method accord<strong>in</strong>g to European Respiratory Society/American Thoracic Society task<br />
force (40) us<strong>in</strong>g the NIOX equipment (Nitric Oxide Monitor<strong>in</strong>g System; Aerocr<strong>in</strong>e,<br />
Sweden).<br />
Study III:<br />
<strong>Lung</strong> <strong>function</strong> measurement <strong>in</strong> neonates<br />
<strong>Lung</strong> <strong>function</strong> was assessed dur<strong>in</strong>g sedation by <strong>in</strong>fant spirometry at 1 month apply<strong>in</strong>g<br />
the raised volume rapid thoracic compression technique (RVRTC). The method,<br />
equipment, data collection and analysis was performed <strong>in</strong> agreement with ATS/ERS<br />
standards (2). Equipment was calibrated and tested prior to every lung <strong>function</strong> test. An<br />
<strong>in</strong>flatable “squeeze”-jacket was wrapped around the <strong>in</strong>fant's chest and abdomen. A<br />
subsequent <strong>in</strong>flation of the jacket provided the passive expiration and flow was<br />
measured us<strong>in</strong>g a pneumotachograph with an aircushion facemask (123, 133, 134). The<br />
<strong>in</strong>fant was adm<strong>in</strong>istered three <strong>in</strong>flations reach<strong>in</strong>g a transrespiratory pressure of 2 kPa<br />
with passive deflations between each. A compression force transmitt<strong>in</strong>g an additional<br />
pressure of 2 kPa was then applied via the squeeze-jacket to the thorax and abdomen,<br />
lead<strong>in</strong>g to an airway open<strong>in</strong>g of pressure of 4 kPa for forced expirations. Basel<strong>in</strong>e flow<br />
was measured as the Forced Expiratory Volume at the first 0.5 second (FEV 0.5 ) (123,<br />
133). Other parameters not reported <strong>in</strong> this thesis comprised FVC, forced expiratory<br />
flow at 25% of FVC (FEF 25 ), forced expiratory flow at 50% of FVC (FEF 50 ) and forced<br />
expiratory flow at 75% of FVC (FEF 75 ). All parameters were measured five times at<br />
basel<strong>in</strong>e and three times at each challenge step, us<strong>in</strong>g the median value for FEV 0.5 to<br />
decide on the cont<strong>in</strong>ued provocation. Tidal flow was also measured but not reported <strong>in</strong><br />
this thesis; <strong>in</strong>dexes comprised tidal volume (V T ), respiratory frequency, peak tidal<br />
expiratory flow (PTEF), expiratory time as ratio of respiratory cycle time, time to reach<br />
PTEF (T PTEF ), and T PTEF /expiratory time ratio (T PTEF /T E ) (123, 133).<br />
The software def<strong>in</strong>ed FVC as the first plateau on the volume-time curve, and only<br />
<strong>measurements</strong> with FVC appear<strong>in</strong>g after 0.5 seconds, and with FEV 0.5 be<strong>in</strong>g smaller<br />
36