Cardiopulmonary mechanics in anesthetized pigs and dogs

¹ The Third (Boston University) Surgical Research Laboratory, Boston City Hospital, Boston, Massachusetts

Ventilatory mechanics and pulmonary hemodynamics were investigated in 39 mongrel dogs and 19 pigs under Nembutal anesthesia. It was found that the pig lung is much less compliant than the dog lung but resembles the human lung if the elastic properties are compared with respect to lung weight or functional residual capacity. The pulmonary artery pressure in the pig was found to be around 42 cm H₂O. The flow resistance of the pulmonary vasculature of the pig is approximately 12 times as great as that of the human lung and 2–3 times greater than in the canine lung. The compliance of the pulmonary artery is correspondingly decreased. The pig appears to be a more suitable animal for the study of pulmonary vasomotion than dog or man.