Effects of hyperbaric oxygen in cryobiologic wounds

Abstract

Hyperbaric oxygen therapy (HBO) has been helpful in treating radiation burn lesions, osteomyelitis, gangrenous wounds, necrotic sites, and injuries caused by tissue hypoxia [5, 7]. For these reasons HBO could be a possible choice for a study to better define the role of hypoxia in the pathogenesis of cryobiologic wounds. Liquid oxygen, as employed in the HBO sessions described in this study, because of its ease of application can be used to show the importance of the same oxygen in the genesis and in the healing process of lesions [4, 7, 8]. For this purpose the effects of hyperbaric and normal oxygen conditions were tested on healing cryolesions experimentally induced in Winster rats. Test subjects were 20 Winster rats weighing between 200 and 220 g, housed individually in stainless steel cages and fed Purina rodent laboratory chow and tap water ad libitum. One thermocouple needle was used to measure in-depth temperature. The rats were divided into two groups of ten animals each. All were anesthetized with intraperitoneal injection of 0.5 ml ketamine. Skin epilation on two symmetrical areas of the dorsum ( 2 3 cm diameter) was done in all rats. Each area was treated with a double freeze-thaw cycle (the second immediately after the first) to 4 0 ~ using liquid nitrogen with the open spray technique (Frigitronic). The freezing time was 45 s and the thawing time was about 80 s. One group of rats was treated with HBO. The HBO session started immediately after the second thawing. HBO was accomplished by flushing a 45 pressure chamber with 100% oxygen up to 2.3 ATA. In this way HBO works on rats both locally and systemically. The treatment sessions were once a day for 45 min each, 5 days a week (pressurization and depressurization took