Electrophysiological assessment in patients with long term hypoxia

OBJECTIVE: To evaluate visual evoked potentials (VEP) patterns in chronic obstructive pulmonary disease (COPD) patients who were compliant with supplemental oxygen treatment relative to non-compliant COPD patients. METHODS: This prospective study protocol was reviewed and approved by the local ethical committee of Selcuk University and the research was performed in the Department of Neurology, Elbistan State Hospital, Kahramanmaras, Turkey from May to October 2014. Blood gas measurements and pulmonary function tests were carried out in patients with advanced stage COPD. The VEP was assessed in both eyes in both compliant and non-compliant patients. RESULTS: The study included 43 patients; 24 (55.8%) of the patients were not in compliance with their supplemental oxygen treatment, while 19 patients (44.2%) received adequate oxygen treatment. There was no statistically significant difference between patients with regards to pulmonary function test results and blood gas measurements. The VEP latency was significantly greater in both eyes of the non-compliant patients. CONCLUSION: Previous studies have reported prolonged VEP latencies in inflammatory diseases of the central nervous system. Similar electrophysiological findings were observed in our study and we propose that this may be due to oxidative stress, and inflammation that occurs secondary to chronic ischemia.