Effects of a Modified Ambulance Night Shift System on Fatigue and Physiological Function among Ambulance Paramedics

Abstract

In the present study, we modified a night shift system for an ambulance service so that ambulance paramedics were assured of taking a nap, and examined the effects of this new system on the fatigue and physiological function of ambulance paramedics. Methods: Ten ambulance paramedics at a fire station in the center of a large city in Japan voluntarily enrolled as subjects in this field study. They worked a 24-h shift system. There were two teams of 5 ambulance paramedics in the fire station. Three ambulance paramedics per shift usually provided the emergency services. In the traditional system, the ambulance paramedics had to deal with all emergency calls throughout a 24-h shift (T-shift). In the modified system, 2 ambulance paramedics were allotted time for naps in the 21:00-3:00 (C-shift) or 3:00-8:30 (Bshift) shift by the addition of another a firefighter (Dshift). Results: There were fewer emergency dispatches and nap time was longer in the B-and Cshifts than in the T-shift. Parasympathetic nerve activities during naps in B-and C-shifts were higher than in the T-shift. The results of critical flicker fusion frequency and 3-choice reaction time in the B-shift at 7:30 tended to be higher and shorter than that in Tshift. Conclusions: The results of this study suggest that the modified night shift which ensured time for ambulance paramedics to take long, restful power naps alleviated subjective fatigue, and improved physiological function which are often adversely affected by night workload. (J Occup Health 2009; 51: 204-209)

Effects of Fatigue on Immune Function in Nurses Performing Shift Work

“…Fatigue was evaluated at four time points (the beginning of day shift, the end of day shift, the beginning of night shift and the end of night shift) by a questionnaire for work-related fatigue feelings, the "Jikaku-sho shirabe" designed by the Industrial Fatigue Research Committee of the Japan Society of Occupational Health 15,16) . This questionnaire was developed to evaluate trends in feelings of fatigue due to work, and factorial validity and internal consistency have been verified 17) .…”

The Shift Length, Fatigue, and Safety Conundrum in EMS

“…11 However, the frequency of complaints about drowsiness and local pain was higher at the end of the 24-hour shift among subjects with less nap time than among subjects with more nap time. 11 Van der Ploeg and Kleber, in 2003, studied how fatigue was related to health symptoms. 10 In this study, 10% of EMS clinicians were at risk of fatiguerelated sick leave or disability.…”

“…4 The 2009 study by Takeyama et al enrolled 10 paramedics who worked 24-hour shifts in Japan. 11 The authors found no meaningful differences in subjective and objective measures of fatigue (e.g., reaction time, temperature, and heart rate) between subjects with shorter versus longer nap periods. 11 However, the frequency of complaints about drowsiness and local pain was higher at the end of the 24-hour shift among subjects with less nap time than among subjects with more nap time.…”

“…4,8,9 The current data are hampered by varying sample sizes and possible selection bias, limiting the ability to generalize to a broader EMS workforce as a whole. 4,8,10,11 Nevertheless, these studies estimate that between 10% and 55% of EMS clinicians suffer from severe mental and/or physical fatigue. 4,8,10 For comparison, about four in 10 general U.S. workers self-report fatigue (38%; 95% confidence interval [CI] 37.4, 38.5).…”

“…It is not often feasible to measure body temperature, heart rate, pupil dilation/movement, reaction time, errors in performing tasks, or test of cognition or memory in large study samples. 11,[20][21][22] At best, previous research suggests that multiple dimensions of fatigue (e.g., mental and physical) are common among EMS clinicians. Investigators and decision makers should address the methodologic gaps in this research, which are fundamental and foundational to any stance on fatigue and shift structure in EMS.…”