Effect of Task Load Interventions on Fatigue in Emergency Medical Services Personnel and Other Shift Workers: A Systematic Review

Figures & data

Figure 1. PRISMA 2009 Flow Diagram for PICO#7 PROSPERO 2016:CRD42016040114.

Table 1. Synthesis of findings on the impact of task load interventions on critical and important outcomes

OBSERVATIONAL STUDIES
			Important Outcomes
Author, Year	RefID PMID#	Study Design	Personnel Safety	Patient Safety^*	Personnel Performance^†	Acute Fatigue^‡	Cost to System
Karhula et al., 2013 (12)	RefID-1399	Prospective cohort study design	—	—	—	Favorable	—
	PMID-24079918
Baulk et al., 2007 (13)	RefID-2396	Prospective cohort study design	—	—	Favorable	Favorable	—
	PMID-n/a
Takahashi et al., 2006 (18)	RefID-2085	Observational study (panelstudy design)	—	—	—	No Impact	—
	PMID-17190723
Dorrian et al., 2011 (14)	RefID-1057	Prospective cohort study design	—	—	—	Favorable	—
	PMID-20691425
Grech et al., 2009 (19)	RefID-1228	Prospective cohort study design	—	—	—	Mixed/ Inconclusive	—
	PMID-19586219

Findings are classified as favorable in support of lower levels of task load (or workload), unfavorable, mixed/inconclusive, or no impact for mitigating fatigue, mitigating fatigue-related risk, and/or improving sleep.

^* Includes quality of care.

^† Includes external subjective ratings of the study subject's performance including perceived satisfaction with the subject's performance.

^‡ Includes acute states of fatigue, sleepiness, and alertness.

Table 2. GRADE evidence profile table

Quality assessment
№ of studies	Study design	Risk of bias	Inconsistency	Indirectness	Imprecision	Other considerations	Impact / Effect	Quality	Importance
Personnel Performance (as measured by psychomotor vigilance test [PVT] reaction time and lapses)
1	Observational studies	Very serious^*,†,‡,§,║	Not serious	Serious^#	Serious^**	None	Pooled Effect Not Estimable: One prospective observational study (Baulk et al., 2007) reported better performance on the PVT during low workload periods for one of 2 observed shifts. Findings characterized as favorable towards lower workload to mitigate fatigue and/or fatigue-related risk. [Total sample size n = 20]	⊕◯◯◯ VERY LOW	IMPORTANT
Acute Fatigue (as measured by perceived sleepiness and fatigue instruments)
5	Observational studies	Very serious ^*,†,‡,§,║	Very serious^††	Serious^#	Serious^**	None	Pooled Effect Not Estimable: One observational study (13) showed mixed/inconclusive associations between workload and indicators of acute fatigue (19). Three studies (Karhula et al., 2013; Baulk et al., 2007; and Dorrian et al., 2011) were believed to have shown a positive relationship between workload and indicators of acute fatigue, such that lower workload was associated with lower fatigue and/or fatigue-related risks (12, 13, 14). One study (Takahashi et al., 2006) showed no association between workload and acute fatigue (18). Three of five studies characterized as favorable towards lower workload to mitigate fatigue. [Median sample size n = 90, min = 20, max = 112]	⊕◯◯◯ VERY LOW	IMPORTANT
Personnel Safety
0							not estimable	—	IMPORTANT
Cost to System
0							Not estimable	—	IMPORTANT

^* No concealment of outcome(s).

^† Method/technique for measuring task load (workload) is subjective and may provide inaccurate information.

^‡ The timing of measurement of task load (workload) may lead to very high or very low values of the variable of interest.

^§ No random assignment.

^║ Study participants may differ from non-participants in some meaningful way.

^# Shift workers other than EMS personnel.

^** Small sample size. Below optimal information size (Guyatt et al., 2011, PMID-21839614).

^†† Two of 5 showed mixed/inconclusive associations between workload and acute fatigue measures. One study showed no relationship. Two showed a positive association (higher workload associated with higher acute fatigue).

Karhula K, Harma M, Sallinen M, Hublin C, Virkkala J, Kivimaki M, Vahtera J, Puttonen S. Association of job strain with working hours, shift-dependent perceived workload, sleepiness and recovery. Ergonomics. 2013;56(11):1640–51. https://doi.org/10.1080/00140139.2013.837514.

 PubMed Web of Science ®Google Scholar

Baulk SD, Kandelaars KJ, Lamond N, Roach GD, Dawson D, Fletcher A. Does variation in workload affect fatigue in a regular 12-hour shift system? Sleep and Biological Rhythms. 2007;5(1):74–7. https://doi.org/10.1111/j.1479-8425.2006.00249.x.

 Web of Science ®Google Scholar

Takahashi M, Nakata A, Haratani T, Otsuka Y, Kaida K, Fukasawa K. Psychosocial work characteristics predicting daytime sleepiness in day and shift workers. Chronobiology international. 2006;23(6):1409–22. https://doi.org/10.1080/07420520601100963.

 PubMed Web of Science ®Google Scholar

Dorrian J, Baulk SD, Dawson D. Work hours, workload, sleep and fatigue in Australian Rail Industry employees. Applied ergonomics. 2011;42(2):202–9. https://doi.org/10.1016/j.apergo.2010.06.009.

 PubMed Web of Science ®Google Scholar

Grech MR, Neal A, Yeo G, Smith S, Humphreys M. An examination of the relationship between workload and fatigue within and across consecutive days of work: is the relationship static or dynamic? Journal of occupational health psychology. 2009;14(3):231–42. https://doi.org/10.1037/a0014952.

 PubMed Web of Science ®Google Scholar