Host Resistance to Hemorrhagic Shock X. Induction of Resistance by Shock Plasma and by Endotoxins. ∗

Summary and conclusions

Rabbits made tolerant to bacterial endotoxin tolerate an otherwise lethal exposure to hemorrhagic shock. Whereas normal, i.e. non-tolerant, rabbits are dead after 6 hours of shock in spite of having received all the blood removed, tolerant rabbits are in satisfactory condition after 6 hours in spite of having received none of the blood removed. They respond promptly when transfused at the end of 6 hours and recover completely. The same results are secured in rabbits made tolerant to, i.e. pretreated with, shock plasma. Therefore, there is reason to consider the toxin in shock plasma an endotoxin. In the rabbit tolerant to endotoxin the blood taken after 6 hours in shock is free of the toxin causing irreversibility, which is in the blood of non-tolerant rabbits in shock. In the rabbit tolerant to shock the granulocytopenic response is distinctly different from that in the non-tolerant animal. The response is less intense and recovery to a normal or above normal count occurs while the rabbit is still in shock. In the non-tolerant rabbit the granulocytopenia persists throughout the shock period. The induction of tolerance to hemorrhagic shock by shock plasma as well as by endotoxin supports the view that a bacterial factor is responsible for irreversibility to transfusion in hemorrhagic shock. The fact that rabbits tolerant to hemorrhagic shock can resist a dose of shock blood or plasma that is lethal to non-tolerant rabbits, and that their bloods do not contain the toxin which develops in non-tolerant rabbits, supports the view that tolerance to hemorrhagic shock is due to the maintenance or enhancement of the normal capacity to neutralize bacteria endotoxin.