Role of pulmonary innervation in canine in situ lung-perfusion preparation: a new model of neurogenic pulmonary oedema.

1. In situ canine lungs were perfused in the presence or absence of the nerves which coursed to the heart and lungs (the cardiopulmonary nerves, CPN). 2. A right heart-bypassed preparation was made first, so that the respiratory and circulatory conditions could be controlled beforehand. It was then switched to a lung-perfusion preparation, in which the lungs receive all influences of sudden cessation of the brain and systemic circulations solely via the CPN. Hydrostatic mechanisms causing pulmonary oedema were excluded by adjusting the pulmonary arterial pressure under 300 mmH2O (less than 24 mmHg). 3. Accumulation of extravascular lung water and the rate of reservoir blood loss were significantly lower in the CPN-severed group than in the CPN-intact group. 4. After perfusion of 90 min, total loss of reservoir blood was correlated significantly with extravascular water content in lungs. The former was larger than the latter. 5. Elevation of left atrial pressure caused an increase in the rate of reservoir blood loss. When the CPN was severed, the relation between these two parameters was shifted to the right. 6. These findings indicate a CPN-mediated genesis of permeability pulmonary oedema.