title: Skin changes following minor trauma.
abstract: OBJECTIVE
  Bruises are currently evaluated by visual inspection, and little is known about the first phase after injury. The temporal development of fresh injuries must be accurately described to be able to age bruises in a reliable manner. Color changes in a bruise caused by hemoglobin breakdown products will depend on the severity of the trauma, and thus on the local immune response in the skin. It is therefore important to relate the nature of the impact to the temporal tissue responses.
  
  
  METHODS
  Controlled injuries were inflicted on anesthetized domestic pigs. Trauma was induced either by a pendulum device, or by paintballs released using pressurized air. The speed of the projectiles was recorded using a high speed camera. Biopsies and reflection spectra (400-850 nm) were collected from normal and bruised skin. The experiments were approved by the national animal research authority.
  
  
  RESULTS
  The temporal development of the injury was found to depend strongly on the weight and speed of the object. Low speed, blunt objects did not cause persistent skin changes. However, deep muscular bleeding could be found in most cases. High speed, light weight objects caused a rapidly developing bruise. These bruises were fully developed within 15-20 minutes. No deep muscular hemorrhages were observed in those cases. White blood cells (neutrophilic granulocytes) could be found in biopsies from high speed injuries. The amount of white blood cells depended on the time between injury and collection of the biopsies.
  
  
  CONCLUSIONS
  Further investigations utilizing a larger range of object weight and velocities are required to be able to fully classify minor traumatic injuries. Preliminary results indicate that this can be achieved by controlled experiments using a porcine model. Reflectance spectroscopy was found to be a useful tool to study immediate skin reactions to the trauma.
authors.affiliation: Department of Electronics and Telecommunications, Norwegian University of Science and Technology, N-7491 Trondheim, Norway. Lise.Randeberg@iet.ntnu.no
authors.forename: Lise Lyngsnes
authors.initials: LL
authors.lastname: Randeberg
authors.forename: Andreas M
authors.initials: AM
authors.lastname: Winnem
authors.forename: Neil E
authors.initials: NE
authors.lastname: Langlois
authors.forename: Eivind L P
authors.initials: EL
authors.lastname: Larsen
authors.forename: Rune
authors.initials: R
authors.lastname: Haaverstad
authors.forename: Bjørn
authors.initials: B
authors.lastname: Skallerud
authors.forename: Olav A
authors.initials: OA
authors.lastname: Haugen
authors.forename: Lars O
authors.initials: LO
authors.lastname: Svaasand
mesh_terms: D000818:Animals; D001707:Biopsy, Needle; D002196:Capillaries / Q000473:pathology; D003288:Contusions / Q000473:pathology*; D004890:Erythema / Q000473:pathology; D005260:Female; D006454:Hemoglobins / Q000032:analysis; D006470:Hemorrhage / Q000473:pathology; D023421:Models, Animal; D009135:Muscular Diseases / Q000473:pathology; D009504:Neutrophils / Q000473:pathology; D010100:Oxygen / Q000097:blood; D010781:Photography; D012039:Regional Blood Flow; D012867:Skin / Q000098:blood supply / Q000293:injuries* / Q000473:pathology*; D013057:Spectrum Analysis; D013552:Swine
chemical_list: D006454:Hemoglobins; C100003:deoxyhemoglobin; D010100:Oxygen