Lung function measurements in children - copsac

Low sRaw reflected as steep loops. The inclinations of the loops were "lying" down
with rising resistance (Figure 3).
Figure 3: sRaw loops before and after provocation in a young child with asthma
BTPS correction was done automatically by the software when the result was analyzed.
sRaw measurement was assessed during regular breathing free of artefacts caused by
e.g. swallowing, vocalization, coughing or leakage around the facemask, which could be
detected as abnormal (open or asymmetric) loops on the on-line display. The decision to
whether accept or reject a measurement was immediately done after the measurement
by the observer. sRaw from one run was calculated as the median value of at least five
technically satisfactory loops with similar configuration and inclination (10-12).
In the center agreement study each of the seven children performed in total six runs. The
local operator made the two first runs, and then switched the operator to PP which made
two runs and finally did two runs with the local operator again.
In the normative study duplicate measurements (two runs) were done by a local
observer.
Statistical analyses
SAS version 9.1 was used for statistical analyses.
Study I: We used ANOVA with unbalanced block design to analyze differences due to
center, child, center specific observer, accompanying observer (PP) and age of the child.
15