OBJECTIVETo study therapeutic effects by using different oxygen therapies in rats with acute carbon dioxide poisoning, to select the best oxygen therapy technology for patients with acute carbon dioxide poisoning on the spot.

METHODSSixty healthy male Sprague-Dawley rats were randomized into normal control group, carbon dioxide exposure group, hyperbaric oxygen treatment group (pressure 2 ATA, FiO(2)100%), high concentration of atmospheric oxygen treatment group (FiO(2)50%), low concentration of atmospheric oxygen treatment group (FiO(2)33%). After treated with different oxygen in rats with acute carbon dioxide poisoning, arterial pH, PO2 and PCO2 of rats were detected, in addition observe pathological changes of lung tissue and brain tissue.

RESULTSThe arterial pH (7.31 ± 0.06) and PO2 [(68.50 ± 15.02) mm Hg] of carbon dioxide exposure group were lower than those of control group [pH (7.42 ± 0.02) and PO2 (92.83 ± 8.27) mm Hg], PCO2 [(71.66 ± 12.10) mm Hg] was higher than that of control group [(48.25 ± 2.59) mm Hg] (P < 0.05); the arterial pH (hyperbaric oxygen treatment group 7.37 ± 0.02, high concentration of atmospheric oxygen treatment group 7.39 ± 0.03, low concentration of atmospheric oxygen treatment group 7.38 ± 0.02) and PO2 of oxygen treatment groups [hyperbaric oxygen treatment group, high concentration of atmospheric oxygen treatment group, low concentration of atmospheric oxygen treatment group were (82.25 ± 12.98), (84.75 ± 11.24), (83.75 ± 16.77) mm Hg, respectively] were higher than that of carbon dioxide exposure group, PCO2 [hyperbaric oxygen treatment group, high concentration of atmospheric oxygen treatment group, low concentration of atmospheric oxygen treatment group were (52.25 ± 4.95), (51.75 ± 4.82), (52.66 ± 5.61) mm Hg, respectively] was lower than that of carbon dioxide exposure group (P < 0.05); there was no significant difference of the arterial pH, PO2 and PCO2 between oxygen treatment groups and control group (P > 0.05); there was no significant difference of the arterial pH, PO2 and PCO2 among oxygen treatment groups (P > 0.05). There was large area of bleeding of lungs in rats with carbon dioxide poisoning, the bleeding of lungs in rats with high concentration of atmospheric oxygen treatment and low concentration of atmospheric oxygen treatment was better than the rats with carbon dioxide poisoning, there was no abnormal appearance of lungs in rats with hyperbaric oxygen treatment. The light microscope observation showed that there were diffuse bleeding and exudation of lungs in rats with carbon dioxide poisoning, the bleeding and exudation of lungs in rats with high concentration of atmospheric oxygen treatment and low concentration of atmospheric oxygen treatment were better than the rats with carbon dioxide poisoning, there were only minor bleeding and exudation of lungs in rats with hyperbaric oxygen treatment. There was no difference of brain in anatomy and microscopy among all groups, there were no significant bleeding, edema, cell degeneration and necrosis.

CONCLUSIONSLung pathology in acute carbon dioxide poisoning rats with hyperbaric oxygen treatment is better than the rats with high concentration of atmospheric oxygen treatment and low concentration of atmospheric oxygen treatment, there is no significant difference of effect between high concentration of atmospheric oxygen treatment group and low concentration of atmospheric oxygen treatment group, however, the results of blood gas analysis and lung pathology than the exposure group improved, so qualified medical unit for hyperbaric oxygen therapy as soon as possible, hyperbaric oxygen treatment facilities in the absence of circumstances, the emergency treatment of early oxygen is also a good measure.