title: Teammate familiarity and risk of injury in emergency medical services.
abstract: OBJECTIVE
  We investigated the association between teammate familiarity and workplace injury in the emergency medical services (EMS) setting.
  
  
  METHODS
  From January 2011 to November 2013, we abstracted a mean of 29 months of shift records and Occupational Safety Health Administration injury logs from 14 EMS organisations with 37 total bases located in four US Census regions. Total teammate familiarity was calculated for each dyad as the total number of times a clinician dyad worked together over the study period. We used negative binomial regression to examine differences in injury incidence rate ratios (IRRs) by familiarity.
  
  
  RESULTS
  We analysed 715 826 shift records, representing 4197 EMS clinicians and 60 701 unique dyads. We determined the mean shifts per dyad was (5.9, SD 19.7), and quartiles of familiarity were 1 shift worked together over the study period, 2-3 shifts, 4-9 shifts and ≥10 shifts worked together. More than half of all dyads worked one shift together (53.9%, n=32 739), 24.8% of dyads 2-3 shifts, 11.8% worked 4-9 shifts and 9.6% worked ≥10 shifts. The overall incidence rate of injury across all organisations was 17.5 per 100 full-time equivalent (FTE), range 4.7-85.6 per 100 FTE. The raw injury rate was 33.5 per 100 FTEs for dyads with one shift of total familiarity, 14.2 for 2-3 shifts, 8.3 for 4-9 shifts and 0.3 for ≥10 shifts. Negative binomial regression confirmed that dyads with ≥10 shifts had the lowest incidence of injury (IRR 0.03; 95% CI 0.02 to 0.04).
  
  
  CONCLUSIONS
  Familiarity between teammates varies in the EMS setting, and less familiarity is associated with greater incidence of workplace injury.
authors.affiliation: Department of Emergency Medicine, Carolinas Medical Center, Charlotte, North Carolina, USA.
authors.forename: P Daniel
authors.identifier: http://orcid.org/0000-0002-8189-0919
authors.initials: PD
authors.lastname: Patterson
authors.affiliation: Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Weaver
authors.affiliation: Section on Biomarkers and Prediction Modeling, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Douglas P
authors.initials: DP
authors.lastname: Landsittel
authors.affiliation: Heinz School of Public Policy and Management, Tepper School of Business, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA.
authors.forename: David
authors.initials: D
authors.lastname: Krackhardt
authors.affiliation: Department of Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, The State University of New York, Buffalo, New York, USA.
authors.forename: David
authors.initials: D
authors.lastname: Hostler
authors.affiliation: Department of Public Health Sciences, College of Medicine, Medical University of South Carolina, Charleston, South Carolina, USA.
authors.forename: John E
authors.initials: JE
authors.lastname: Vena
authors.affiliation: Institute for Simulation & Training, University of Central Florida, Orlando, Florida, USA.
authors.forename: Ashley M
authors.initials: AM
authors.lastname: Hughes
authors.affiliation: Department of Psychology, Rice University, Houston, Texas, USA.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Salas
authors.affiliation: Department of Emergency Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
authors.forename: Donald M
authors.initials: DM
authors.lastname: Yealy
mesh_terms: D000062:Accidents, Occupational / Q000706:statistics & numerical data*; D000328:Adult; D004632:Emergency Medical Services / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D007398:Interpersonal Relations; D008297:Male; D008875:Middle Aged; D010348:Patient Care Team / Q000458:organization & administration; D012189:Retrospective Studies; D012306:Risk; D017132:Workplace / Q000706:statistics & numerical data*; D014947:Wounds and Injuries / Q000453:epidemiology*
keywords: management, risk management; paramedics; prehospital care; safety