Biomedical Engineering Reference
In-Depth Information
Ta b l e 7 . 1 2
Biometric and spirometric parameters of the children diagnosed with cystic fibrosis
and the healthy children used for comparison. Values are presented as mean
standard deviation
values; % pred: predicted values; VC: vital capacity; FEV1: forced expiratory volume in one sec-
ond; FEF: forced expiratory flow; MEF75/25: mean expiratory flow at 75 %, respectively at 25 %
capacity; NA: data not available
±
Cystic fibrosis
(10)
Healthy
(16)
Female/male
4/6
13/3
Age (yrs)
14
.
44
±
6
.
21
9
.
66
±
0
.
47
Height (m)
1
.
49
±
0
.
15
1
.
39
±
0
.
07
Weight (kg)
39
.
89
±
11
.
67
32
.
3
±
6
.
34
FEF/VC
%pred
86
.
51
±
36
.
12
NA
FEV
1
/VC
%pred
95
.
71
±
9
.
42
NA
MEF
75
/
25 (l)
2
.
08
±
1
.
13
NA
predicted values (% pred) in a healthy subject with the same biometric details. Qual-
ity control of spirometry is given by the ATS criteria (American Thoracic Society),
with the software allowing detection of non-acceptable manoeuvres. From the 19
patients with clinical diagnosis of asthma, 16 presented normal respiratory response
by spirometry, and will be further referred to as normal-to-the exam (NE) patients.
The underlying reason for this was that the patients had a
controlled asthma
.
The predicted values in
R
6 are very close to the measured values, in both healthy
and asthmatic children, as depicted by Fig.
7.17
. This then supports the spirometric
data from Table
7.10
, which shows values close to 100 % of the predicted values
in all subjects, thus denoting the NE patients. The high standard deviation values in
Table
7.10
for the spirometric indices are due to the few asthmatic patients which
were not normal to the exam, also visible in Fig.
7.17
with
R
6 values higher than
the rest of the group. As observed from Fig.
7.18
, there was a linear dependence
between the
FEV
1
/VC
% index and height in asthmatic children, in agreement with
similar studies from literature [
33
,
121
].
The complex impedance values for the healthy and asthmatic children obtained
using (
3.8
) are depicted in Figs.
7.19
and
7.20
. The equivalent Bode plots are given
in Figs.
7.21
and
7.22
. Table
7.13
presents the results obtained from the identifica-
tion of model parameters.
It can be observed that for the inductance
L
r
and its corresponding fractional-
order parameter
α
r
, the confidence intervals are overlapping; hence, there are no
significant differences from these parameters between the three groups. The elas-
tance 1
/C
r
and its corresponding fractional-order parameter
β
r
were significantly
different between the groups, leading to significantly different values for the tis-
sue damping
G
r
(
p
0
.
01), as observed in
Fig.
7.23
. The corresponding boxplots for tissue damping
G
r
and tissue elastance
H
r
in the three groups: healthy, asthma before bronchial challenge, and asthma after
bronchial challenge test are given in Fig.
7.23
. The boxplots for the quality factor
0
.
01) and tissue elastance
H
r
(
p
