Does Hyperbaric Oxygen Therapy, Cause Long Term Spirometric Changes In Smokers Versus Non-smokers?

Introduction: Multiple conflicting studies of spirometric changes in patients undergoing hyperbaric oxygen therapy (HBOT) have been previously reported. There have not been any reports to date that follow the long term spirometric changes of former smokers and life long non-smokers who completed a course of HBOT. There is uncertainty whether the spirometric changes are due to former smokers reverting back to smoking or that these are a true HBOT affect. The purpose of this study is to evaluate the long term spirometric parameters of former smokers who reverted back to smoking versus non-smokers after a course of HBOT. Methods: Spirometry was performed on former smokers and life long non-smokers before HBOT and one year after (post), with a minimum of 20 HBOT. Particular attention was directed to determine whether former smokers resumed or that non-smokers began smoking after their HBOT. Results: A total of 24 patients were evaluated in the study, (17 males, 7 females) with the average age of 65 years old. Six patients resumed smoking after completing HBOT, 11 continued to be smoke free and 7 patients were not able to be contacted. No life long non-smokers started smoking. Post-HBOT spirometric measurements showed a significant difference in the degradation of flow dependent variables (FEV1/FVC and FEF 25%-75%), in patients who continue to smoke post HBOT. Conclusions: There is a statistical difference decrease in FEV1/FVC and FEF 25%-75% values in former smokers who resumed smoking after HBOT. On the other hand, there is no significant change in any of the parameters tested in life long non-smokers in this preliminary report.