COPD exacerbation, very severe COPD with hypoxemia at low altitude (FEV1/FVC <0.7, FEV1 <40% predicted, oxygen saturation on room air <92% at 750 m).
Comorbidities such as uncontrolled cardiovascular disease, i.e., unstable systemic arterial hypertension, coronary artery disease; previous stroke; OSA; pneumothorax in the last 2 months.
Internal, neurologic, rheumatologic or psychiatric disease including current heavy smoking (>20 cigarettes per day)
Known renal failure or allergy to acetazolamide and other sulfonamides

NCT03177837_exc_T1
Condition
COPD exacerbation
NCT03177837_exc_T2
Qualifier
very severe
NCT03177837_exc_T3
Condition
COPD
NCT03177837_exc_T4
Condition
hypoxemia
NCT03177837_exc_T5
Qualifier
low altitude
NCT03177837_exc_T6
Measurement
FEV1/FVC
NCT03177837_exc_T7
Value
<0.7
NCT03177837_exc_T8
Measurement
FEV1
NCT03177837_exc_T9
Value
<40% predicted
NCT03177837_exc_T10
Measurement
oxygen saturation
NCT03177837_exc_T11
Qualifier
room air
NCT03177837_exc_T12
Value
<92%
NCT03177837_exc_T13
Qualifier
750 m
NCT03177837_exc_T14
Condition
cardiovascular disease
NCT03177837_exc_T15
Qualifier
uncontrolled
NCT03177837_exc_T16
Condition
Comorbidities
NCT03177837_exc_T17
Qualifier
unstable
NCT03177837_exc_T18
Condition
systemic arterial hypertension
NCT03177837_exc_T19
Condition
coronary artery disease
NCT03177837_exc_T20
Temporal
previous
NCT03177837_exc_T21
Condition
stroke
NCT03177837_exc_T22
Condition
OSA
NCT03177837_exc_T23
Condition
pneumothorax
NCT03177837_exc_T24
Temporal
in the last 2 months
NCT03177837_exc_T25
Scope
uncontrolled cardiovascular disease, i.e., unstable systemic arterial hypertension, coronary artery disease; previous stroke; OSA; pneumothorax in the last 2 months
NCT03177837_exc_T26
Qualifier
Internal
NCT03177837_exc_T27
Qualifier
neurologic
NCT03177837_exc_T28
Qualifier
rheumatologic
NCT03177837_exc_T29
Qualifier
psychiatric
NCT03177837_exc_T30
Condition
disease
NCT03177837_exc_T31
Temporal
current
NCT03177837_exc_T32
Observation
smoking
NCT03177837_exc_T33
Qualifier
heavy
NCT03177837_exc_T34
Value
>20
NCT03177837_exc_T35
Measurement
cigarettes per day
NCT03177837_exc_T36
Scope
>20 cigarettes per day
NCT03177837_exc_T37
Scope
heavy smoking
NCT03177837_exc_T38
Scope
heavy smoking (>20 cigarettes per day)
NCT03177837_exc_T39
Scope
Internal, neurologic, rheumatologic or psychiatric
NCT03177837_exc_T40
Condition
renal failure
NCT03177837_exc_T41
Condition
allergy
NCT03177837_exc_T42
Drug
acetazolamide
NCT03177837_exc_T43
Drug
sulfonamides
NCT03177837_exc_T44
Qualifier
other
NCT03177837_exc_T45
Scope
acetazolamide and other sulfonamides