Occurrence of bacteremia during and after hemorrhagic shock

Abstract

In recent research, hemorrhagic shock and septic shock have been studied as two separate entities. We have developed a treated model of hemorrhagic shock in which unrestrained and unanesthetized rats are bled to a mean arterial pressure of 30 torr until 80% of the maximum shed volume must be returned. Rats are maintained preshock and treated post shock with a 20% glucose-electrolyte solution. Survival of these animals is 62% at 24 hours post shock and all animals are dead at 72 hours post shock. Blood cultures obtained during shock become positive at 2 hours into the shock period and are significant compared to controls at 3 to 5 hours of shock (p less than 0.0001). Blood cultures obtained after the period of shock are significantly positive at 24 and 48 hours post shock (p less than 0.05) compared to controls. Intrashock cultures are monomicrobial; the majority of post-shock cultures are polymicrobial. All cultured organisms are normal rat enteric flora. Histologic changes of renal failure are also demonstrated post shock. We suggest that bacterial invasion, possibly from the gut, plays a role in the sepsis seen in patients following severe hemorrhagic shock. Sepsis may precede rather than follow the immune incompetence which accompanies shock.