Randomized, placebo controlled trial evaluating the effect of acetazolamide on cognition in lowlanders with chronic obstructive pulmonary disease travelling from 760 m to 3200 m.

This is a randomized, placebo-controlled, double-blind parallel trial evaluating the effect of acetazolamide (375 mg per day) vs. placebo on visuomotor learning performance at altitude (Tuja Ashu, 3200 m). Randomization to acetazolamide or placebo will be carried out after baseline measurements in Bishkek (760 m).

Visuomotor learning performance will be tested by Motor Task Manager (MTM). The MTM requires the subjects to reach visual targets with a hand-held cursor. During progression of the test, the movement direction from the cursor on the computer screen will increasingly differ from the direction of the hand movement, forcing the unaware subject to implicitly adapt to the imposed cursor rotation. This test assesses a subjects ability to visuomotor adaption, perception and attention. Furthermore, as the task will be performed in the evening and after sleep in the next morning, the investigators will be able to assess overnight improvement of implicit learned skills.

Inclusion Criteria:

• Male and female patients, age 18-75 yrs.
• COPD diagnosed according to GOLD, FEV1 40-80% predicted, SpO2 ≥92% at 750 m.
• Born, raised and currently living at low altitude (<800m).
• Written informed consent.

Exclusion Criteria:

• 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