EFFECT OF DIAPHRAGMATIC LYMPHATIC CONTAMINATION ON CAUDAL MEDIASTINAL NODE LYMPH FLOW IN UNANESTHETIZED SHEEP

Abstract

Our purpose was to determine the effect of diaphragmatic
lymphatics on steady state caudal mediastinal
node (CMN) or lung lymph flow in the unanesthetized
sheep. After standard lung lymph fistula
preparation, in which the CMN efferent was cannulated,
nine sheep had an additional extensive cautery
procedure in the right chest along the esophagus
and diaphragm to sever any systemic lymphati cs
entering the CMN. This was followed by a similar
cautery procedure on the left side, one week later.
There was no difference in steady state lymph flow,
QL, or in the lymph-to-plasma, LIP protein ratio in
any paired study when comparing the bilateral cautery
procedure with the right side alone, nor was
there any difference in these parameters when this
data was compared with that from thirty standard
lymph fistula preparations. In addition, diaphrag matic
lymphatics were cannulated in five sheep.
Mean QL immediately post-surgery was 1.6 ± 0.4
ml/hr compared to a CMN QL of 6.1 ± 0.4 ml /hr.
By six hou rs after surgery, diaphragmatic QL decreased
to 0.4 ± 0.2 while CMN flow remained relatively
steady. We conclude that residual diaphragmatic
lymphatics, if any, entering the caudal mediastinal
lymph node, not removed by the standard
preparation do not appear to affect steady state
CMN lymph flow or LIP ratio, in the normal unanesthetized
sheep, especially if measurements are obtained
at least 6 hours after surgery.