Technique of right lymphatic duct cannulation for pulmonary lymph collection in an acute porcine model.

The pig is an increasingly preferred model for biomedical research, including studies for pulmonary pathophysiology. However, in piglets, the technique for cannulating the right lymphatic duct, which is subject to more anatomical variations and technically more demanding than that in dogs, has not been described. Our technique evolved to enable this collection of porcine lung lymph in acute experiments. The lymphatic ampulla is cannulated via one of the cervical lymphatics. The right lymphatic duct is invariably dorsal to the cranial vena cava and classically leads to the lymphatic ampulla. Yet in 18% of our pigs, cannulation was difficult or not feasible because the lymphatic duct either drained directly into the cranial vena cava at a distance from the lymphatic ampulla, or into the axillary lymph node of the first rib or the caudal deep cervical lymph nodes. Gently squeezing back regurgitated blood in the lymphatic ampulla before tying the suture and frequently withdrawing lymph with a syringe when the flow is small enabled us to collect clear lymph, usually immediately after completing the cannulation. The rate of lymph flow varied widely (1.7 +/- 0.6 ml/hr) and increased when the left atrial pressure was raised. The lymph protein was 2.8 +/- 0.2 g% with lymph/plasma protein ratio at 0.55 +/- 0.04. The anatomical variations encountered in our 34 dissections, as well as the technical maneuvers found to be useful in the successful cannulation and collection of the porcine lung lymph, are described in detail.