ABSTRACT
In this chapter, the authors provide a detailed "how-to" manual for the chronic lung-lymph fistula preparation in sheep as they currently use it in their laboratories. They present new data relevant to the use of the model. The authors discuss scientific issues surrounding the application of the sheep model. They review ruminant lymphatic system anatomy and physiology to provide a framework. Multiple thoracotomies have traditionally been used to prepare chronic lung-lymph fistulas in sheep because of the need to address two issues. The first issue is the contribution of systemic sources to caudal mediastinal lymph node (CMN) efferent duct lymph. The second issue is that two factors may operate independently or in tandem to increase lung-lymph flow: increased microvascular hydrostatic pressure and increased permeability of the endothelial barrier to liquid and protein. In some instances, CMN efferent duct lymph flow decreases, presumably because the partial obstruction of systemic venous blood flow decreases pulmonary vascular pressures.
