4
· AMS brains swell more on ascent to high altitude
· Swelling associated with h ADC, consistent with
vasogenic edema at onset of AMS
· h CBV cannot be ruled out
Interim Summary:
Vasogenic Edema in
AMS
ICP: What's New?
· No new data
on ICP or CSVB in AMS
· Preliminary Data
on AMS Susceptibles
· New techniques
have promise to reveal role
of h ICP and i CSVB in AMS
MRI and Doppler+MAP
· Pulsatile blood flow to the
brain g instantaneous
and periodic
in
intracranial volume (ICV)
and ICP
· Using MRI blood and
CSF flow measurements,
the
of ICV and ICP are
derived
· Elastance index
ICP Measurements: MR-
ICP
Alperin
et. al. Radiology. 2000; 217 (3); 877
885
Elastance Index vs. Invasive ICP in
Patients with Intra-Ventricular Catheter
R
2
= 0.95
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
4
8
12
16
20
24
28
ICP (mmHg) (EVD)
E
l
a
s
t
a
n
c
e
I
n
d
e
x
(
M
R
)
Alperin
et. al. Radiology. 2000; 217 (3); 877
885
AMS Pathophysiology
· Oxidative stress, role for free radicals?
Neuro-oxidative cascade with hypoxia
Molecular damage to BBB, inflammation
Difficult to measure directly
· LH, CPK, lower pain threshold in AMS
EPR electron paramagnetic resonance
(Bailey, 2003)
·
free radicals, IL-6, suggest oxidation of iron
· A role for antioxidants? Maybe
(Bailey, 2003)
