title: Factors affecting the accuracy of chest compression depth estimation.
abstract: OBJECTIVE
  We aimed to estimate the accuracy of visual estimation of chest compression depth and identify potential factors affecting accuracy.
  
  
  METHODS
  This simulation study used a basic life support mannequin, the Ambu man. We recorded chest compression with 7 different depths from 1 to 7 cm. Each video clip was recorded for a cycle of compression. Three different viewpoints were used to record the video. After filming, 25 clips were randomly selected. Health care providers in an emergency department were asked to estimate the depth of compressions while watching the selected video clips. Examiner determinants such as experience and cardiopulmonary resuscitation training and environment determinants such as the location of the camera (examiner) were collected and analyzed. An estimated depth was considered correct if it was consistent with the one recorded. A multivariate analysis predicting the accuracy of compression depth estimation was performed.
  
  
  RESULTS
  Overall, 103 subjects were enrolled in the study; 42 (40.8%) were physicians, 56 (54.4%) nurses, and 5 (4.8%) emergency medical technicians. The mean accuracy was 0.89 (standard deviation, 0.76). Among examiner determinants, only subjects' occupation and clinical experience showed significant association with outcome (P=0.03 and P=0.08, respectively). All environmental determinants showed significant association with the outcome (all P<0.001). Multivariate analysis showed that accuracy rate was significantly associated with occupation, camera position, and compression depth.
  
  
  CONCLUSIONS
  The accuracy rate of chest compression depth estimation was 0.89 and was significantly related with examiner's occupation, camera view position, and compression depth.
authors.affiliation: Department of Emergency Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Jung Hee
authors.initials: JH
authors.lastname: Kang
authors.affiliation: Department of Emergency Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Won Chul
authors.initials: WC
authors.lastname: Cha
authors.affiliation: Department of Emergency Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Minjung Kathy
authors.initials: MK
authors.lastname: Chae
authors.affiliation: Department of Emergency Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Hang A
authors.initials: HA
authors.lastname: Park
authors.affiliation: Department of Emergency Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Sung Yeon
authors.initials: SY
authors.lastname: Hwang
authors.affiliation: Department of Emergency Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Sang Chan
authors.initials: SC
authors.lastname: Jin
authors.affiliation: Department of Emergency Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Tae Rim
authors.initials: TR
authors.lastname: Lee
authors.affiliation: Department of Emergency Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Tae Gun
authors.initials: TG
authors.lastname: Shin
authors.affiliation: Department of Emergency Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Min Seob
authors.initials: MS
authors.lastname: Sim
authors.affiliation: Department of Emergency Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Ik Joon
authors.initials: IJ
authors.lastname: Jo
authors.affiliation: Department of Emergency Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Keun Jeong
authors.initials: KJ
authors.lastname: Song
authors.affiliation: Department of Emergency Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Joong Eui
authors.initials: JE
authors.lastname: Rhee
authors.affiliation: Department of Emergency Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Yeon Kwon
authors.initials: YK
authors.lastname: Jeong
keywords: Cardiopulmonary resuscitation; Feedback; Manikins; Patient care team; Video recording