title: [Comparison of two methods of local anesthetic administration using three phantom tissue models].
abstract: BACKGROUND
  Local anesthetic is often administered around surgical wounds to reduce pain. It remains unknown, however, how the agent diffuses into tissue, or whether the method of administration has any impact on the drug diffusion. We evaluated drug-diffusion areas around wounds after administering a dummy agent by needle injection (NI) and direct infiltration (DI) using three phantom tissue models : agar, sponge, and pork rib.
  
  
  METHODS
  Blue-colored water, a dummy substitute for local anesthetic, was administered in the vicinity of surgical wounds simulated by three tissue models. After the administration, blue-stained cross sectional areas and diffusion capacities were compared.
  
  
  RESULTS
  The stained cross sections of the DI tissue were uniform, while those of the NI tissue were globular and centered around the needle point. The sectional area and diffusion capacity were significantly greater in the DI tissue than in the NI tissue in the agar model, though no significant differences between the administration methods were observed in the other models.
  
  
  CONCLUSIONS
  The direct infiltration method is likely to diffuse local anesthetic into tissue more uniformly and more extensively than the needle injection method.
authors: Department of Anesthesiology and Intensive Care Medicine, Jichi Medical University Saitama Medical Center, Saitama 330-8503.
authors: Shiho
authors: S
authors: Yamato
authors: Osamu
authors: O
authors: Nagata
authors: Takanori
authors: T
authors: Murayama
mesh_terms: D000779:Anesthetics, Local / Q000008:administration & dosage*; D004058:Diffusion; D007267:Injections / Q000379:methods*; D008953:Models, Anatomic; D010149:Postoperative Pain / Q000517:prevention & control
chemical_list: D000779:Anesthetics, Local