Time out! Is timepiece variability a factor in critical care?

BACKGROUND: Accurate documentation of time is essential in critical care for treatments, interventions, research, and medicolegal and quality improvement activities. OBJECTIVES: To assess use of timepieces in critical care and to determine practical methods for improving their accuracy. METHODS: Providers were surveyed to identify timepieces used during routine and emergency care. Times displayed on standard unit and personal timepieces were compared with coordinated universal time. Four models of atomic clocks were assessed for drift for 6 weeks and for resynchronization for 1 week. Bedside monitors were manually synchronized to coordinated universal time and were assessed for drift. RESULTS: Survey response was 78% (149/190). Nurses (n = 93), physicians (n = 32), and respiratory therapists (n = 24) use wall clocks (50%) and personal timepieces (46%) most frequently during emergencies. The difference from coordinated universal time was a median of -4 minutes (range, -5 minutes to +2 min) for wall clocks, -2.5 minutes (-90 minutes to -1 minute) for monitors, and 0 minutes (-22 minutes to +12 minutes) for personal timepieces. Kruskal-Wallis testing indicated significant variations for all classes of timepieces (P<.001) and for personal timepieces grouped by discipline (P=.02). Atomic clocks were accurate to 30 seconds of coordinated universal time for 6 weeks when manually set but could not be synchronized by radiofrequency signal. Drift of bedside monitors was 1 minute. CONCLUSIONS: Timepieces used in critical care are highly variable and inaccurate. Manually synchronizing timepieces to coordinated universal time improved accuracy for several weeks, but the feasibility of synchronizing all timepieces is undetermined.