Use of Imaging Agent to Determine Postoperative Indwelling Epidural Catheter Position

BACKGROUND: Epidural anesthesia is widely used to provide pain relief, whether for surgical anesthesia, postoperative analgesia, treatment of chronic pain, or to facilitate painless childbirth. In many cases, however, the epidural catheter is inserted blindly and the indwelling catheter position is almost always uncertain. METHODS: In this study, the loss-of-resistance technique was used and an imaging agent was injected through the indwelling epidural anesthesia catheter to confirm the position of its tip and examine the migration rate. Study subjects were patients scheduled to undergo surgery using general anesthesia combined with epidural anesthesia. Placement of the epidural catheter was confirmed postoperatively by injection of an imaging agent and X-ray imaging. RESULTS: The indwelling epidural catheter was placed between upper thoracic vertebrae (n = 83; incorrect placement, n = 5), lower thoracic vertebrae (n = 123; incorrect placement, n = 5), and lower thoracic vertebra-lumbar vertebra (n = 46; incorrect placement, n = 7). In this study, a relatively high frequency of incorrectly placed epidural catheters using the loss-of-resistance technique was observed, and it was found that incorrect catheter placement resulted in inadequate analgesia during surgery. CONCLUSIONS: Although the loss-of-resistance technique is easy and convenient as a method for epidural catheter placement, it frequently results in inadequate placement of epidural catheters. Care should be taken when performing this procedure.

MORPHOLOGICAL AND STRUCTURAL CHARACTERISTICS OF THE PERITONEAL LYMPHATIC CAPILLARY NETWORKS / 解剖学报

Objective Peritoneal lymphatic features are studied to provide necessary data for understanding transport capabilities of the endothelial and mesothelial cells. Methods Enzyme\|histochemical staining methods were employed to investigate organization of the lymphatic networks and their endothelial ultrastructures in the monkey peritoneum using light,scanning and transmission electron microscopy. Results 5' Nase positive initial lymphatics showed extensive network,obvious valve like structures and numerous blind ends.The calibre of lymphatics with extremely irregular lumen varied greatly from 40 to 120?m.Lymphatic endothelium was usually separated from mesothelium by a small quantity of loose connective tissue,or they directly contacted each other in some areas.No basal lamina occurred between the peritoneum and the lymphatics originating from milky spots in the omentum and mesovarium.Milky spots are oval or round visible bodies aggregated by macrophages and lymphocytes.Both the endothelium of lymphatic lacunae and the mesothelium that forms the peritoneal stomata,represent a strong 5' Nase activity.Abundant microfibrils attached the stomatal edge. Conclusion The distribution and structure of peritoneal initial lymphatics reveal significant regional variations,and lymphatic endothelium has a close morphological and functional relationship with the mesothelium. [