Abstract
We studied the effect of decreased plasma colloid osmotic pressure (COP) on lung lymph flow in anesthetized dogs.
In the first group, COP was reduced by slow infusion of saline while the hydrostatic pressure (HP) in the pulmonary vascular bed was maintained at normal levels. The reduction of COP caused an increase in lung lymph flow. When COP was reduced by 50 percent and 80 percent of control values respectively, pulmonary lymph flow was increased 2-fold in the former and 5-fold in the latter from the base line level. In the second group, COP was reduced with an elevation of HP by rapid infusion of saline. Lung lymph flow was increased markedly as compared with the first group with reduced COP at normal vascular pressure. Pulmonary lymph flow was increased 5-fold when COP was reduced to 50 percent of control values and pulmonary artery pressure (PAP) was elevated to 10mmHg from the base line levels and moreover, when COP was reduced by 80 percent and PAP was elevated by 20mmHg of the control, respectively, pulmonary lymph flow was increased 12-fold of control values.
When the change in pulmonary lymph flow was plotted against that in COP and PAP in the two groups, it was found that lymph flow in the lung increased almost linearly with the elevation in PAP-COP.
