Endotoxemia was demonstrated in over 90% (28 of 30) of a series of animals subjected to one of four different types of refractory shock. Microscopic study of the lungs showed that the changes characteristic of the lung lesion in shock did not occur unless an endotoxemia developed and persisted until death. When pretreatment by inducing resistance to endotoxin or by intraintestinal administration of nonabsorbable antibiotics prevented the endotoxemia or converted a persistent to a transient endotoxemia, there was a corresponding reduction in the incidence of the lung lesion and the mortality.
Cuevas P, de la Maza LM, Gilbert J, Fine J. The Lung Lesion in Four Different Types of Shock in Rabbits. Arch Surg. 1972;104(3):319-322. doi:10.1001/archsurg.1972.04180030067015