ESTIMATION OF LYMPH-FLOW BY RELATING LYMPHATIC PUMP FUNCTION TO PASSIVE FLOW CURVES

Active pumping in postnodal lymphatic vessels is an important factor i nfluencing lymph flow. However, the output of the lymphatic PumP also depends on the rate of flow into the pump. This arrangement is similar to the blood circulation where cardiac output depends on the rate of blood flow through the veins into the heart (venous return) and on the pumping characteristics of the heart itself (cardiac function curves) . One common way to analyze the blood circulation rate is to interrela te venous return and cardiac function curves. In this study, we used a similar technique to analyze lymph flow. We used lymphatic flow vs. o utflow pressure (passive flow) relationships for nonpumping lymphatics to represent the inflow of lymph to the lymphatic pump. We used data on the pumping characteristics of postnodal lymphatic vessels to gener ate relationships between lymphatic pump outflow and pump inflow press ure (pump function curves), and then interrelated these curves. The re sults were not only similar to previously measured lymph flow data obt ained from experimental animals, but also support the observation that under normal circumstances lymph flow is periodic and in surges (acti ve pumping) but in edematogenic states lymph flows more continuously ( i.e., passively).