title: Synchronization of timepieces to the atomic clock in an urban emergency medical services system.
abstract: OBJECTIVE
  Erroneous time documentation of emergency treatment caused by the variation in the accuracy of timepieces has profound medical, medicolegal, and research consequences. The purpose of this study was to confirm the variation of critical timepiece settings in an urban emergency care system noted in previous studies and to implement and monitor the results of a prospective program to improve time synchronization.
  
  
  METHODS
  Timepieces (n = 393) used by firefighters, paramedics, and emergency physicians and nurses were randomly sampled immediately before and at two time intervals (1 and 4 months) after attempted synchronization to the US atomic clock standard. The setting on each timepiece was compared with the atomic clock. From the data, a mathematical simulation estimated the number of time-related documentation errors that would occur in 2,500 simulated cardiac arrest cases using timepieces with accuracy similar to those found in the EMS system before and after attempted synchronization.
  
  
  RESULTS
  Before attempted synchronization, the timepieces had a mean error of 2.0 (95% confidence interval 1.8 to 2.3) minutes. One month after attempted synchronization, the mean error decreased significantly to .9(.8 to 1.1) minute. However, it increased to 1.7 (1.5 to 1.9) minutes within 4 months. Mathematical simulation before attempted synchronization predicted that 93% of cardiac arrest cases would contain a documentation error of 2 minutes or more and that 41% of cases would contain a documentation error of 5 minutes or more. Attempted synchronization cut the 2-minute documentation error rate in half and reduced the 5-minute documentation error rate by three fourths. However, the error rates were predicted to return to baseline 4 months after attempted synchronization.
  
  
  CONCLUSIONS
  Emergency medical timepieces are often inaccurate, making it difficult to reconstruct events for medical, medicolegal, or research purposes. Community synchronization of timepieces to the atomic clock can reduce the problem significantly, but the effects of a one-time attempted synchronization event are short-lived.
authors.affiliation: Department of Emergency Medicine, Virginia Commonwealth University/Medical College of Virginia, Richmond, USA.
authors.forename: J P
authors.initials: JP
authors.lastname: Ornato
authors.forename: M L
authors.initials: ML
authors.lastname: Doctor
authors.forename: L F
authors.initials: LF
authors.lastname: Harbour
authors.forename: M A
authors.initials: MA
authors.lastname: Peberdy
authors.forename: J
authors.initials: J
authors.lastname: Overton
authors.forename: E M
authors.initials: EM
authors.lastname: Racht
authors.forename: W G
authors.initials: WG
authors.lastname: Zauhar
authors.forename: A P
authors.initials: AP
authors.lastname: Smith
authors.forename: K A
authors.initials: KA
authors.lastname: Ryan
mesh_terms: D003644:Death Certificates; D004282:Documentation / Q000706:statistics & numerical data*; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D006323:Heart Arrest / Q000401:mortality; D006786:Hospitals, Urban / Q000706:statistics & numerical data*; D006801:Humans; D008962:Models, Theoretical; D010348:Patient Care Team / Q000706:statistics & numerical data; D012015:Reference Standards; D015203:Reproducibility of Results; D013995:Time; D017748:Time Management; D014768:Virginia