Wilderness Medical Society snowmass 2005 Page 58
9
ENaC
Na
+
- K
-
ATPase
ALVEOLAR SPACE
INTERSTITIUM
Amiloride
Na
+
Water
Viagra for HAPE?
Sildenafil reduces hypoxic PHT acutely
0
20
40
60
80
100
120
SaO2%
PAP
SBP
HR
Baseline
Placebo
Sildenafil
Nitric oxide - overview
NO
cGMP
eNOS
Vascular
muscle
relaxation
Shear
Receptors
Hypoxia
L-arginine
PDE's
Acetazolamide to Prevent HAPE?
· Empirically used for 2 decades
· New evidence
Berg et al, WEM, 2004
· Az prevents HAPE in rats
Swenson et al in press
Control
ACZ
ACZ8
M
e
a
n
P
u
l
m
o
n
a
r
y
A
r
t
e
r
i
a
l
P
r
e
s
s
u
r
e
[
m
m
H
g
]
P
u
l
m
o
n
a
r
y
V
a
s
c
u
l
a
r
R
e
s
i
s
t
a
n
c
e
[
d
y
n
s
-
1
c
m
-
5
]
12
14
16
18
20
22
24
26
*
*
*
*
§
§
§
§
§
§
§
§
Normoxia
Hypoxi a
1
2
3
4
5
350
400
450
500
550
600
650
700
750
Time [h]
*
*
*
*
§
§
§
§
§
§
§
§
Control
ACZ
ACZ8
Control
ACZ
ACZ8
M
e
a
n
P
u
l
m
o
n
a
r
y
A
r
t
e
r
i
a
l
P
r
e
s
s
u
r
e
[
m
m
H
g
]
M
e
a
n
P
u
l
m
o
n
a
r
y
A
r
t
e
r
i
a
l
P
r
e
s
s
u
r
e
[
m
m
H
g
]
P
u
l
m
o
n
a
r
y
V
a
s
c
u
l
a
r
R
e
s
i
s
t
a
n
c
e
[
d
y
n
s
-
1
c
m
-
5
]
P
u
l
m
o
n
a
r
y
V
a
s
c
u
l
a
r
R
e
s
i
s
t
a
n
c
e
[
d
y
n
s
-
1
c
m
-
5
]
12
14
16
18
20
22
24
26
*
*
*
*
§
§
§
§
§
§
§
§
12
14
16
18
20
22
24
26
*
*
*
*
§
§
§
§
§
§
§
§
Normoxia
Hypoxi a
1
2
3
4
5
350
400
450
500
550
600
650
700
750
Time [h]
*
*
*
*
§
§
§
§
§
§
§
§
1
2
3
4
5
350
400
450
500
550
600
650
700
750
Time [h]
*
*
*
*
§
§
§
§
§
§
§
§
Acetazolamide Abolishes Hypoxic
Pulmonary Vasoconstriction
