Pulmonary Air Embolization in the Dog: I. Hemodynamic Changes on Repeated Embolizations

Abstract

An experimental model is described for studying the effects of inert material emboli on pulmonary hemodynamics. Air, 1 ml/kg bodyweight, was injected directly into the pulmonary artery in 21 dogs. Within 20 seconds the pulmo nary arterial pressure rose 140%. Pulmonary arterial wedge and left atrial pressures were almost unchanged. Cardiac output decreased 28%. Aortic pressure made a brief negative deflection of 12%. Pulmonary vascular resistance increased 248%, systemic vascular resistance 30%. All changes disappeared within 13 minutes. Basal levels were not influenced despite manifold repetitions. Repeat embolizations caused similar results with small variations. Different types of ventilation and breathing gases, and thora cotomy with pulmonary dissection did not obscure the pattern. Plastic beads induced effects similar in principle but longer lasting.

Key Words:

• Air embolism
• Pulmonary
• hemodynamics