title: Preliminary Measures of Instructor Learning in Teaching Junctional Tourniquet Users.
abstract: BACKGROUND
  The objective of the present study was to assess the effect of instructor learning on student performance in use of junctional tourniquets.
  
  
  METHODS
  From a convenience sample of data available after another study, we used a manikin for assessment of control of bleeding from a right groin gunshot wound. Blood loss was measured by the instructor while training users. The data set represented a group of 30 persons taught one at a time. The first measure was a plot of mean blood loss volumes for the sequential users. The second measure was a plot of the cumulative sum (CUSUM) of mean blood loss (BL) volumes for users.
  
  
  RESULTS
  Mean blood loss trended down as the instructor gained experience with each newly instructed user. User performance continually improved as the instructor gained more experience with teaching. No plateau effect was observed within the 30 users. The CUSUM plot illustrated a turning point or cusp at the seventh user. The prior portion of the plot (users 1-7) had the greatest improvement; performance did not improve as much thereafter. The improvement after the seventh user was the only change detected in the instructor's trend of performance.
  
  
  CONCLUSIONS
  The instructor's teaching experience appeared to directly affect user performance; in a model of junctional hemorrhage, the volume of blood loss from the manikin during junctional tourniquet placement was a useful metric of instructor learning. The CUSUM technique detected a small but meaningful change in trend where the instructor learning curve was greatest while working with the first seven users.
authors.forename: John F
authors.initials: JF
authors.lastname: Kragh
authors.forename: James K
authors.initials: JK
authors.lastname: Aden
authors.forename: Stacy
authors.initials: S
authors.lastname: Shackelford
authors.forename: Michael A
authors.initials: MA
authors.lastname: Dubick
mesh_terms: D004521:Educational Measurement; D006119:Groin; D006470:Hemorrhage / Q000209:etiology / Q000628:therapy*; D006801:Humans; D059032:Learning Curve; D008348:Manikins; D012771:Shock, Hemorrhagic / Q000517:prevention & control*; D000066908:Simulation Training; D000070260:Teacher Training; D014111:Tourniquets; D014948:Wounds, Gunshot / Q000150:complications / Q000628:therapy*