Anesthesia associated depression in lymphocyte traffic: less with regional anesthesia than with general anesthesia in sheep.

In the sheep single peripheral lymph node model of Hall and Morris, it is possible to cannulate efferent and afferent lymphatic vessels for long-term study of cells and substances in lymph and for short- and long-term infusions. By supporting the sheep in sternal recumbency (upright) to avoid positional alterations in lymphocyte traffic in short-term studies and by precise timing and measurement of lymph output and cell counts, it is possible to accumulate data on lymphocyte output into efferent lymph on a consecutive, cumulative basis and to detect long- and short-term alterations in lymphocyte traffic. With this model, studies on the effects of general and regional anesthesia were carried out on 42 unstimulated primary peripheral lymph nodes of sheep in vivo. The lymphocyte traffic depressing effects of general anesthesia were found to be significantly less when regional epidural anesthesia was employed. The duration of depression also was less. In the general anesthesia studies, the depth of depression in lymphocyte traffic appeared related to the dose and length of anesthesia. These alterations may play important roles in the immunologic responses to anesthetic compounds and approaches.