Effect of hyperbaric oxygen therapy on postoperative cognitive dysfunction in elderly patients undergoing general anesthesia

Abstract

Objective To evaluate the effect of hyperbaric oxygen (HBO) therapy on postoperative cognitive dysfunction (POCD) in elderly patients undergoing general anesthesia. Methods A total of 112 patients, aged 65-75 yr, of American Society of Anesthesiologists physical status Ⅱ or Ⅲ, undergoing elective non-cardiac surgery with general anesthesia, were randomly divided into control group (C group, n=54) and HBO group (n=58). Patients were exposed to hyperbaric oxygen in a hyperbaric oxygen chamber once a day from day 3 to day 12 after surgery in both groups.Pressure was slowly increased to 2 atmosphere absolute within 20 min, pure oxygen was inhaled for 35 min by mask, 5 min later pure oxygen was inhaled for another 35 min, oxygen inhalation was then stopped and pressure was slowly increased to 1 atmosphere absolute in HBO group.Patients inhaled air at 1 atmosphere absolute for 70 min in C group.Cognitive function score was assessed using Mini-Mental State Examination, language ability test, visual identification function test, digit span backwards task and Hasegawa′s Dementia Scale (HDS) at 2 days before surgery and 7 and 13 days after surgery.The development of POCD was recorded. Results Compared with the baseline at 2 days before surgery, language ability test, digit span backwards task and HDS scores were significantly decreased at 7 and 13 days after surgery in C group, and digit span backwards task scores were significantly decreased at 7 days after surgery in HBO group(P<0.05 or 0.01). The language ability test and HDS scores were significantly higher, and the incidence of POCD was lower at 7 and 13 days after surgery in HBO group than in C group (P<0.05). Conclusion HBO therapy can reduce POCD in elderly patients undergoing general anesthesia. Key words: Hyperbaric oxygen; Aged; Anesthesia, general; Cognitive disorders