Hemodynamic studies in experimental toxemia of the dog.

The following experiments demonstrate that the severity of toxemia is proportional to the degree of reduction in blood flow to the pregnant uterus. Blood pressure and blood flow variations were studied in 21 nonpregnant and pregnant dogs following the placement of a progressive stricture on the abdominal aorta below the renal arteries. The immediate effect of the stricture was a mild hypertension in half of the pregnant dogs; in addition, in all the dogs, the blood flow progressively dropped in the arteries below the stricture (femoral and uterine) while it remained constant in the arteries above (ovarian and renal). In 3 of 5 pregnant dogs the delayed effect of the aortic stricture was hypertension associated with all the other signs of experimental toxemia. Removal of the aortic stricture after 10 days immediately improved the blood flow below the stricture. No noticeable preferential distribution of blood toward the pregnant uterus was noted during the constriction.