Variation in Retinal Venous Blood Saturation During Hypoxia Between Smokers and Non-Smokers

Abstract

Abstract: : Purpose: To compare changes in venous blood saturation during hypoxia between smokers and non-smokers. Methods: : All procedures were approved by an IRB, and informed consent obtained. Thirty-two oximetry images (12 male, 20 female, 8 smoker, and 24 non-smoker) were obtained in 14 normal healthy adults (mean 37.1 years, SD=9.1) using a newly developed digital retinal oximeter. Measurements were taken while subjects were breathing room air and a mixture of room air and nitrogen. During hypoxia, arterial saturations were reduced to approximately 90%. Images were analyzed to determine arterial and venous oxygen saturation. The levels of venous oxygen saturation during normal oxygen and hypoxic conditions were compared using a Mann-Whitney unpaired u test for the smoking and non-smoking groups. A p>0.05 was considered significant. Results: Hypoxia reduced venous oxygen saturation in the non-smoker group (p = 0.0099) however the reduction in the smoking group was not significant (p = 0.65). There was no significant difference in venous O2sat between smokers and non-smokers. Conclusions: Smokers present with an altered retinal oximetric response to hypoxia.

Keywords: imaging/image analysis: non-clinical