Blood Cultures from Pulmonary Artery and Aorta in Patient with Infected Patent Ductus arteriosus

Abstract

Operation, in cases of subacute bacterial endarteritis superimposed on patent ductus arteriosus, necessitates direct exposure of the pulmonary artery and aorta.^{1, 2, 3} This offers an opportunity to take blood cultures directly from the above structures.

In a recent case, 14 ml of blood were drawn simultaneously from both the pulmonary artery and the aorta. Agar-plate cultures of the blood taken from the pulmonary artery revealed innumerable colonies of Streptococcus viridans. The aortic specimen contained 51 colonies per ml of blood. These quantitative determinations indicate that the bacterial content of the blood entering the lungs differs from that of the blood leaving the lungs (and traversing only the left side of the heart.).

Heretofore the existence of a pulmonary protective barrier, which removes infective material from the circulating blood, has been demonstrated directly only in experimental animals.^4-9 Furthermore, in cases of subacute bacterial endarteritis superimposed on patent ductus arteriosus, it has not been shown as yet whether infective material derived from vegetative foci within the ductus and the adjacent portions of the pulmonary artery, reaches the peripheral circulation by passing through the pulmonary circuit or by entering the aorta through the ductus, or both.

The observations described herein demonstrate directly, that: (1) The lungs play an important rôle in removing infective material from the circulating blood of humans; and (2) in cases of subacute bacterial endarteritis superimposed on patent ductus arteriosus, infective material enters the peripheral circulation, at least in part, through the pulmonary circuit.