Proportions of dog lung lymph in the thoracic and right lymph ducts.

We studied the external lymphatic drainage of the lung in anesthetized dogs, by simultaneously measuring lymph flows from the thoracic duct (TD) and right lymph duct (RLD) during base line and during pulmonary edema. We measured lymph flow for a 2-h base-line period, for 2 h after tying off the thoracic duct above the diaphragm to eliminate nonthoracic lymph contributions, and after giving alloxan. Following alloxan, all dogs developed moderately severe pulmonary edema. In eight dogs the average TD flows were 24.0, 0.9, and 8.2 ml/h and RLD flows were 1.1, 1.3, and 8.4 ml/h, respectively. If we assume that all increases in lymph flow after giving alloxan are due to increased lung lymph flow, then, on the average, 50% of lung lymph drains into the TD and 50% into the RLD. However, among the eight dogs, four had significant increases in TD flow after alloxan (8.9-24.6 ml/h), and four did not. RLD flow increased in all dogs following alloxan. It appears the fraction of lung lymph draining into the TD and RLD can vary greatly amone individual dogs but, on the average, the TD and RLD receive about equal fractions of the pulmonary lymph. In shamoperated control animals TD and RLD lymph flows did not change over a 5-h period.