Optimal dosing as a necessary condition for the efficacy of hyperbaric oxygen therapy in acute ischemic stroke: a critical review.

The effectiveness of hyperbaric oxygen therapy (HBOT) in clinical and experimental acute ischemic stroke (AIS) has been controversial for many years. However, in the literature, no data was found on the dose/effect of HBOT in patients with AIS. We analyzed retrospectively the published data of clinical studies performed in different hyperbaric centers (a total of 265 patients). The dose of HBOT (DHBOT) was calculated considering the product intrabarochamber pO2 (ATA), the duration of a single HBOT exposure (hours), and the number of HBOT treatments. Efficacy of HBOT (EfHBOT) data regarding the number of patients who showed significant clinical improvement of their neurologic status in the course of the treatment HBOT (the percentage of the total number of patients). The level of EfHBOT in each study was compared with a corresponding value of DHBOT. A comparison of the data shows a pronounced tendency for higher values of EfHBOT as the level of the average values of the total DHBOT increases. The coefficient of correlation between these parameters appears to be fairly high (r = 0.92). The maximum possible value of EfHBOT is 100%, which corresponded to the average values of DHBOT at a level of no less than 30 agreed units. The examined data suggest that applying optimal total DHBOT may provide a maximum possible EfHBOT in treating patients with AIS.