Gas exchange after autologous pulmonary embolism in dogs

The ventilatory and arterial blood gas responses to serum-induced thrombi embolized to the pulmonary circulation of the dog have been measured. An increase in rate and minute volume of ventilation independent of the extent of the pulmonary artery obstruction were almost invariably observed. The release of thrombi to the lungs was associated with an arterial-alveolar CO 2 tension difference that was dependent on the extent of arterial obstruction. Significant decreases in arterial O 2 saturation occurred in animals with massive embolization in the presence of a total minute and alveolar ventilation significantly greater than control values. Failure of arterial O 2 concentration to rise to control levels after inhalation of 99.6% O 2 indicated that emboli of the dogs' own blood produced a perfusion defect consistent with a right to left shunt. Submitted on November 2 1, 1960