Biomedical Engineering Reference
In-Depth Information
Example
Calculate the static fluid pressure in the cranium at the end of systole and at the end of diastole.
Assume that the cranium is 30 cm above the aortic valve and that the pressure at systole and dias-
tole is 120 mmHg and 80 mmHg, respectively (see
Figure 3.2
). The density of blood is 1050 kg/m
3
.
Solution
dp
52
ρ
g
z
dz
p
1
ð
g
z
ð
z
1
dp
52
ρ
dz
p
o
z
0
p
p
p
0
52
ρ
g
z
z
z
1
z
0
p
1
2
p
0
52
ρ
g
z
ð
z
1
2
z
0
Þ
p
1
5
p
0
2
ρ
z
0
Þ
End of Systole
g
z
ð
z
1
2
p
1
5
p
0
2
ρ
g
z
ð
z
1
2
z
0
Þ
9
1 mmHg
133
1050
kg
m
3
81
m
s
2
1m
100 cm
p
1
5
120 mmHg
2
:
ð
30 cm
2
0cm
Þ
:
32 Pa
p
1
5
96
:
82 mmHg
End of Diastole
p
1
5
p
0
2
ρ
g
z
ð
z
1
2
z
0
Þ
9
1050
kg
m
3
81
m
s
2
1m
100 cm
1 mmHg
133
p
1
5
80 mmHg
:
ð
30 cm
0cm
Þ
2
2
:
32 Pa
p
1
5
56
:
82 mmHg
FIGURE 3.2
Difference in fluid static pressure between the aortic
valve and the cranium based on height.
30 cm
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