Oxygen therapy in hemorrhagic shock.
Decreased oxygen delivery and cellular hypoxia are important factors in the pathophysiology of hemorrhagic shock. We studied the effects of 100% oxygen at 1 and 3 ATA (atmosphere absolute) in a severe model of hemorrhagic shock induced by bleeding 50% of the total blood volume in rats. Post-treatment with 100% oxygen at 1 and 3 ATA maintained mean arterial blood pressure (MABP) in hemorrhaged rats at significantly higher values compared to untreated controls (P less than 0.01 at 1 and 3 ATA). Treatment with oxygen attenuated the increase in plasma activities of the lysosomal hydrolase cathepsin D (P less than 0.05 at 1 ATA; P less than 0.01 at 3 ATA). Oxygen at 3 ATA also attenuated the plasma accumulation of free amino-nitrogen compounds (P less than 0.05). Furthermore, hyperoxia prevented the final increase in hematocrit (P less than 0.05 at 1 ATA; P less than 0.01 at 3 ATA). Hemorrhaged rats treated with oxygen also exhibited a significantly longer survival time (P less than 0.01 at both doses), and higher survival rates (50% at 1 ATA and 100% at 3 ATA; P less than 0.05 and P less than 0.01, respectively) than untreated shock rats. No significant effect on any of the above mentioned variables was found in hemorrhaged rats treated with 7% oxygen at 3 ATA (oxygen pressure 0.2 ATA), indicating that all salutary effects can be attributed to oxygen and not to the increased ambient pressure per se. Our results indicate that 100% oxygen in normobaric and hyperbaric conditions exerts important beneficial effects in hemorrhagic shock and may be a useful drug for the treatment of this condition.
Bitterman
H
H
Department of Internal Medicine B, Lady Davis Carmel Hospital, Faculty of Medicine, Technion-Israel Institute of Technology, Haifa.
Reissman
P
P
Bitterman
N
N
Melamed
Y
Y
Cohen
L
L
D000818:Animals; D001794:Blood Pressure; D002402:Cathepsin D / Q000097:blood; D006400:Hematocrit; D006931:Hyperbaric Oxygenation; D008297:Male; D010100:Oxygen / Q000008:administration & dosage / Q000627:therapeutic use*; D051381:Rats; D011919:Rats, Inbred Strains; D012771:Shock, Hemorrhagic / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D015996:Survival Rate
D002402:Cathepsin D; D010100:Oxygen