Effect of long-term oxygen therapy on cognitive and neurological dysfunction in chronic obstructive pulmonary disease

The aim of this study was to assess effect of long-term oxygen therapy (LTOT) on the function of central and autonomic nervous system in patients with hypoxaemic chronic obstructive pulmonary disease (COPD). A battery of neuropsychological tests was used together with the Short Test of Mental Status in addition to transcranial Doppler ultrasonography, and five cardiovascular tests as well as a questionnaire on autonomic function. Ten COPD patients, 4 males and 6 females, with a mean age of 65.9 +/- 7.3 (SD) years, were studied at the beginning and after 3 months of LTOT. At start PaO2 was 6.7 +/- 1.1 kPa without oxygen and 9.9 +/- 1.5 kPa after 3 months with oxygen. Our results demonstrate that neuropsychological function, cerebral blood flow velocity and autonomic function were positively influenced after 3 months of LTOT although the changes did not reach statistical significance. The COPD patients were cognitively impaired as compared to age-matched healthy controls. Our findings were consistent with the previous notion of improvement of hypoxic cognitive dysfunction by LTOT.