Effect of increased systemic venous pressure on thoracic duct and peripheral lymph flow in dogs

In congestive heart failure, lymph flow from the cannulated thoracic duct is greatly increased. However, there has been scant data on lymph flow in the intact lymphatic system with systemic circulatory congestion. In the present study, thoracic duct and peripheral lymph flow were qualitatively determined using heated cross-thermocouples in seven mongrel dogs. Central venous pressure was raised artificially by infusing large volumes of crystalloid solution equivalent to a maximum of 30% of body weight. Although both thoracic duct and peripheral lymph flow increased with an intact (closed) lymphatic system, the increase was notably less than with a transected (opened) cervical thoracic duct. With systemic circulatory congestion, cannulated thoracic duct lymph flow circumvents a major lymph impediment to lymph flow (i.e. high central venous pressure) and therefore considerably overestimates in vivo central lymph flow in this condition.