Biomedical Engineering Reference
In-Depth Information
Fig. 7.6
Boxplots for the computed permittivity index
ε
r
in the FO2,
p<
0
.
0081 (
left
)andin
FO4,
p<
0
.
0002 (
right
), in the two groups;
1
: Healthy subjects and
2
: COPD patients
The concluding observation for this section is that in general, FO4 identified
more statistically significant model parameter values than FO2. In Figs.
7.3
-
7.5
FO4
parameters had identified similar variations between healthy and COPD groups.
However, in Fig.
7.6
, one can observe that FO4 identified a more realistic variation
between healthy and COPD groups, i.e. a decreased permittivity index in COPD
than in healthy.
7.3 Implications in Pathology
In the remainder of this chapter, the term
subjects
will refer to healthy volunteers,
whereas the term
patients
will refer to diagnosed volunteers. The forced oscillations
lung function test (FOT) was employed to perform measurements of the input res-
piratory impedance, as described in Sect.
3.1
. The measurement was performed in
the
f
(rad/s).
Drop-out criteria were: (i) technically biased measurements (swallowing, cough-
ing, glottis closure); (ii) fatigue and therefore reduced ability to breath sponta-
neously; and (iii) irregular breathing period. All subjects and patients were in stable
physical conditions at the time of the evaluation.
Written and/or oral consent was obtained from all participants, and in case of
children, from both children and their parents. Further selection of the participants
was performed by oral/written questionnaire ruling out any other respiratory disease
than the one envisaged for the study at the time of measurement or in the past 4
weeks. The remainder of this section presents the data for the participants to whom
these inclusion criteria applied.
∈[
4
,
48
]
(Hz) frequency interval, respectively
ω
∈[
25
,
300
]
7.3.1 FOT Measurements on Adults
The
healthy adult group
evaluated in this study consists of 80 Caucasian volunteers
(students) without a history of respiratory disease, whose lung function tests were
