Humoral Transmission of Cardiorespiratory Changes in Experimental Lung Embolism

Pairs of sheep were connected via a unilateral carotid-jugular anastomosis in fourteen experiments. With the cross circulation open, pulmonary embolism induced in the donor sheep produced a rise in pulmonary arterial pressure, a fall in lung compliance, and an increase in ventilation in the recipient animal. The transmitted effects were more pronounced with barium sulfate lung embolism than with blood clot lung embolism. These observations are consistent with the assumption that in acute experimental lung embolism a humoral agent is being released causing constriction of the lung vessels and airways.