Anatomic variations of efferent duct from caudal mediastinal lymph node in sheep

Abstract

Collection of lymph from the efferent duct of the caudal mediastinal node in sheep is accepted as a reliable method for following lung microvascular fluid and protein filtration. There are significant variations in the efferent duct anatomy, which can complicate the cannulation procedure and, therefore, the success of the preparations. We analyzed the major variations in the efferent duct in 75 consecutive sheep. The majority (59%) had a single efferent duct varying in length, course, and origin fom the caudal mediastinal node; 41% had multiple ducts, often with confluences or bifurcations, making successful cannulation more difficult. It is important to recognize the potential variations in the efferent duct to facilitate useful cannulation.

Structure, blood supply, and lymphatic vessels of the sheep's visceral pleura

“…Staub (1974) has described the general distribution of the intrapulmonary lymphatics and illustrated, by dye injections, the path of the pleural collecting lymphatics. The anatomy of the efferent duct of the caudal mediastinal lymph node also has been described for the sheep (Staub et al, 1975;Landolt et al, 1981). In other ruminants, Baum (1912) drew beautiful colored plates depicting the lung lymph drainage in the ox, and Tanudimadja and Ghoshal(l973) described it in the goat.…”

New method for evaluation of lung lymph flow rate with intact lymphatics in anaesthetized sheep

“…Problems recognized with this technique include abdominal contamination (Drake et al. 1981, Demling & Gunther 1982), anatomical variables in efferent ducts (Landolt et al. 1981) and multiple CMN (May 1970), which may produce over‐ or underestimation of lymph flow rate.…”

“…The classic method to monitor lung lymph is the chronic lung lymph fistula (Staub et al 1975), characterized by measurement of lymph flow and constituents by cannulation of a lymphatic efferent vessel from the caudal mediastinal node (CMN). Problems recognized with this technique include abdominal contamination (Drake et al 1981, Demling & Gunther 1982, anatomical variables in efferent ducts (Landolt et al 1981) and multiple CMN (May 1970), which may produce over-or underestimation of lymph flow rate.…”

New method for evaluation of lung lymph flow rate with intact lymphatics in anaesthetized sheep

“…1981), resulting in an overestimation of lung lymph flow rate and a diluted lymph protein concentration. The second criticism regards the possible presence of multiple efferent ducts of the CMN (Landolt et al. 1981); usually there are two CMNs draining into the thoracic duct (TD) (May 1955), and this may result in underestimation of the lung lymph flow rate, since tube cannulation of only one efferent lymphatic duct of the multiple efferent ducts of the two CMNs is performed.…”

“…The first of these is that possible lymph contamination into the CMN may occur through the diaphragm from abdominal organs (Drake et al 1981), resulting in an overestimation of lung lymph flow rate and a diluted lymph protein concentration. The second criticism regards the possible presence of multiple efferent ducts of the CMN (Landolt et al 1981); usually there are two CMNs draining into the thoracic duct (TD) (May 1955), and this may result in underestimation of the lung lymph flow rate, since tube cannulation of only one efferent lymphatic duct of the multiple efferent ducts of the two CMNs is performed. In addition to these anatomical concerns, physiological criticisms associated with the pumping activity of lymphatics have also been raised (McHale & Meharg 1992, Muthuchamy et al 2003, Aukland 2005.…”