Correlation between tracheal pressure and pulmonary artery pressure in healthy dogs.

The relationship between mean pulmonary artery pressure (PAP) and alveolar pressures, at varying tidal volumes and opposing variable pressure to expiratory flow, was studied in 14 healthy dogs at the end of inspiration and at the end of expiration. Pulmonary blood flow was also studied in 4 dogs. Through the analysis of multiple regression, the equations which show the relation between PAP, tracheal pressure and tidal volume during phases of zero flow were obtained. Our study shows that the co-relation between PAP and tracheal pressure is always highly significant and that, in our experimental conditions, the parameter having the greatest influence on PAP is tracheal pressure, while tidal volume is negligible.