Biomedical Engineering Reference
In-Depth Information
Ta b l e 7 . 6
Biometric and spirometric parameters of the adults diagnosed with kyphoscoliosis. Val-
ues are presented as mean
standard deviation values; % pred: predicted values; VC: vital capacity;
FEV1: forced expiratory volume in one second; FVC: forced vital capacity; Cobb angle: the angle
of spinal deformity (one patient was excluded for it has outlier value for Cobb angle, i.e. 178
◦
;
C
cw
: chest wall compliance; pred
∗
: denotes values predicted from the Cobb angle, according to
[
103
];
R
aw
: airway resistance from bodybox lung function test. All patients were on nocturnal
ventilation
±
Kyphoscoliosis
(9)
Female/male
3/6
Age (yrs)
62
.
25
±
10
.
12
Height (m)
1
.
55
±
0
.
08
Weight (kg)
63
.
25
±
15
.
62
VC
%pred
33
.
25
±
14
.
15
FEV
1
%pred
31
.
62
±
11
.
30
FVC
%pred
34
.
62
±
12
.
12
Cobb angle (
◦
)
75
±
19
.
63
R
aw
(kPa/l/s)
0
.
51
±
0.12
C
cw
pred* (l/kPa)
0
.
98
±
0
.
29
VC
% pred*
65
.
06
±
10
.
48
Fig. 7.7
Bode plots for the
healthy group
in Figs.
7.7
and
7.8
. The real part denotes mainly the mechanical resistance of the
lung tissue, which is generally increased in the COPD group, resulting in a higher
work of breathing. Also, the resistance at low frequencies is much increased in the
COPD group, suggesting increased damping of the lung parenchyma (viscoelasticity
is mainly analyzed at low frequencies).
The estimated and derived model parameter values along with the real, imagi-
nary, and total error values are given in Table
7.7
for the healthy subjects and for the
COPD patients.
Tissue destruction (emphysema, COPD) and changes in air-space size and tis-
sue elasticity are matched with changes in model parameters when compared to
