Hepatic lymphatic mapping: A pilot study for porta hepatis lymph node identification

The status of the porta hepatis lymph nodes in patients with hepatic metast ases from colorectal cancer affects their prognosis and management. Lymphat ic mapping with isosulfan blue dye is well established in breast cancer and melanoma. An animal model consisting of three dogs receiving general anest hesia was utilized. Each dog underwent a laparotomy and increasing doses of isosulfan blue dye were injected into the right medial segment of the live r. Intraoperatively, the presence of blue dye in the porta hepatis region w as determined and the lymph node identified. Continuous physiological monit oring was performed Serum determination of liver function tests, amylase le vels, and white blood cell count were performed preoperatively and on posto perative days 1, 2, 4, and 7. The animals were sacrificed on day 7. A porta l lymph node was identified in each case and there was no perioperative mor bidity or mortality. There were no significant alterations in blood pressur e or heart rate in the animals. There was a dose-responsive decrease in the O-2 saturation as measured by transcutaneous monitoring, but arterial bloo d gas analysis. showed that pO(2) levels remained stable. There were no sig nificant changes in the liver function tests, amylase levels, or white bloo d cell counts. There was a small increase in alkaline phosphatase, which no rmalized by postoperative day 7. Hepatic injection of isosulfan blue dye ap pears to be safe and effective in identifying porta hepatis lymph nodes in the animal model and sets the basis for further study in human subjects.