Comparison of effects of naloxone and catecholamines on acid-base balance in canine hemorrhagic shock.

The present study was conducted to compare the effect of naloxone, an opiate receptor antagonist, with catecholamines on acid-base status and survival in dogs subjected to hemorrhagic shock. Arterial lactic acid concentration which had increased during hemorrhage, decreased significantly (P less than 0.05) in naloxone treated animals but increased further in catecholamine treated dogs. Blood bicarbonate concentration and PCO2 which had markedly decreased 1 hr after hemorrhage recovered significantly (P less than 0.05) in naloxone group of animals. On the other hand bicarbonate and pH declined further in noradrenaline group and remained unchanged in dopamine group. These results as well as better survival rate observed in naloxone treated animals suggest the superiority of naloxone over dopamine and noradrenaline, as an adjunct to blood transfusion in the treatment of hemorrhagic shock.