Lung function measurements in children - copsac

Methods
Designs
Study I:
Six centers in Denmark currently use identical hardware equipment, but software
versions differed between centers (JLAB 4.51, 4.53 with different sub versions, 4.65
and 4.67).
Center agreement
The seven children were brought to each center for sRaw measurements. The children
were not trained in performing lung function measurement before entering the study.
The order of center visits was randomized. At each center the children were measured
by a center specific observer as well as one external observer visiting each center (PP).
The two observers were blinded for each other’s measurements. Measurements in the
individual children were finished within a period of 3 months.
Normative data
The children attended their local center where duplicate measurements were done by a
local observer. The center numbers in the center agreement study represent the same
center numbers in the normative study. Center no. 1-5 provided data for the healthy
cohort. Center no. 6 did not participate in the second part of the study because a local
investigator was unavailable.
Wholebody Plethysmography
Protocol of sRaw measurement
Principle of measurement
Whole body plethysmography was introduced by DuBois in 1956 for specific airway
resistance measurement (53).
Our measurements were conducted in a constant volume whole body plethysmograph
(Master Screen Body; E. Jaeger GmbH, Würzburg, Germany). A transducer measured
pressure changes in the sealed box generated by the thoracic and abdominal movements
during tidal breathing. By calibration of the plethysmograph the changes in pressure
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