The effect of hypoxia on cognitive performance in patients with chronic obstructive pulmonary disease.

Air travel may cause significant hypoxia in passengers with chronic obstructive pulmonary disease (COPD). It is not known whether this level of hypoxia will cause impairment in cognitive function. The aim of this study was to determine the effect of hypoxia on cognitive performance in patients with COPD when Pa(O2) was decreased <6.6 kPa. In ten patients with moderate to severe COPD trail making tasks and complex figure tasks were used to assess cognitive performance when the patients breathed 21% O(2), and when Pa(O2) was decreased to <6.6 kPa. During administration of 21% O(2), Pa(O2) was 9.5 (8.9-10.2) kPa. When Sp(O2) was decreased to 85% via manipulation of the FI(O2) (inspired fraction of oxygen) Pa(O2), decreased to 6.1 (5.9-6.2) kPa. No short term deterioration in visual search, mental flexibility or visuospatial constructional ability was detected when Pa(O2) was decreased to <6.6 kPa. The results show that short term exposure to hypoxia had no adverse effect on cognitive function.