New vascular sheath for subcutaneous drug administration: design, animal testing, and clinical application for pain prevention after angioplasty.

A new vascular sheath design (anesthesia infusion sleeve or AIS) was developed to enable administration of local anesthetics or other medications into the subcutaneous tissue around the insertion site without any additional needle sticks or other manipulation. Design of the system was based upon anatomic measurements of femoral artery depth in 150 patients. Animal studies of prototypes verified subcutaneous delivery using both radiographic methods and direct dissection. The pharmacokinetic profile of plasma lidocaine was also studied in three pigs to document subcutaneous delivery with the AIS. Subsequently a clinical trial of the AIS versus a standard sheath was done in 20 patients undergoing coronary angioplasty. Pain associated with sheath removal was graded using a verbal scale at baseline, during infiltration of the area, and at 1-min intervals during compression for 15 min. Baseline pain was identical in both groups, whereas, during infiltration with lidocaine, pain increased in the standard sheath group and decreased in the AIS group. Pain increased slightly in both groups with initial compression; however, it was significantly less in the AIS group. This difference persisted for several minutes after initial compression. The AIS represents a simple addition to standard sheath protocol offering superior pain control compared to standard technique for sheath removal without the need for systemic analgesics or other medications.