From the Department of Anesthesiology ( J.L.H., A.M.K., D.C.S., E.C.N.), Department of Psychiatry and Neurobehavioral Sciences (M.M.), and Department of Psychiatry and Neurobehavioral Sciences (D.J.C.), University of Virginia Health System, Charlottesville, Virginia; and Department of Anesthesiology, University of California San Francisco, San Francisco, California ( J.A.T.).
BACKGROUND: Residency training requires work in clinical settings for extended periods of time, resulting in altered sleep patterns, sleep deprivation, and potentially deleterious effects on safe performance of daily activities, including driving a motor vehicle.
METHODS: Twenty-nine anesthesiology resident physicians in postgraduate year 2 to 4 drove for 55 min in the Virginia Driving Safety Laboratory using the Driver Guidance System (MBFARR, LLC, USA). Two driving simulator sessions were conducted, one experimental session immediately after the final shift of six consecutive night shifts and one control session at the beginning of a normal day shift (not after call). Both sessions were conducted at 8:00 AM. Psychomotor vigilance task testing was employed to evaluate reaction time and lapses in attention.
RESULTS: After six consecutive night shifts, residents experienced significantly impaired control of all the driving variables including speed, lane position, throttle, and steering. They were also more likely to be involved in collisions. After six consecutive night shifts, residents had a significant increase in reaction times (281.1 vs. 298.5 ms; P = 0.001) and had a significant increase in the number of both minor (0.85 vs. 1.88; P = 0.01) and major lapses (0.00 vs. 0.31; P = 0.008) in attention.
CONCLUSIONS: Resident physicians have greater difficulty controlling speed and driving performance in the driving simulator after six consecutive night shifts. Reaction times are also increased with emphasis on increases in minor and major lapses in attention after six consecutive night shifts.