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What influences safety in paramedicine? Understanding the impact of stress and fatigue on safety outcomes

Abstract Objective The purpose of this study was to build on extant research linking fatigue to safety outcomes in paramedicine by assessing the influence of a multiplicity of workplace stressors, including chronic and critical incident stresses on safety outcomes. Methods A cross‐sectional survey was deployed to 10 paramedic services in Ontario. Validated survey instruments measured operational and organizational chronic stress, critical incident stress, post‐traumatic stress symptomatology (PTSS), fatigue, safety outcomes, and demographics. Analysis of covariance assessed associations of workplace stresses with safety outcomes and corroborated findings using hierarchical linear model and generalized estimating equations (GEE) by taking into account paramedic service when assessing the proposed associations. A non‐responder survey was conducted to asses for demographic differences in those who did and did not complete the survey. Results This survey had a response rate of 40.5% (n = 717/1767); 80% of paramedics reported an injury or exposure to pathogen, 95% reported safety compromising behaviors, and 76% reported medical errors. In the GEE analyses, paramedic injury was significantly related to fatigue (0.13, SE = 0.06, P = 0.020), critical incident stress (0.03, SE = 0.01, P < 0.01), and PTSS (0.03, SE = 0.01, P < 0.01). Safety compromising behaviors were significantly associated with fatigue (0.37, SE = 0.06, P < 0.01), organizational stress (0.06, SE = 0.01, P < 0.01), and critical incident stress (0.01. SE = 0.01, P = 0.017). Medication errors were significantly related to fatigue (0.12, SE = 0.05, P < 0.01). Finally, the bivariate analysis showed increased stress factors and fatigue was associated with increased safety outcomes. Conclusion These findings illustrate that a host of different stressors may influence safety‐related behaviors. For those interested in safety, these findings point to the need for a holistic focus on fatigue and stress in paramedicine.


INTRODUCTION
Within paramedic services, there has been an increasing dialogue about safety culture 1,2 and safety outcomes. 3 This focus on safety in paramedicine is critical, because it works to identify those factors that place both paramedics and patients at risk for psychological and physical injury. When trying to understand safety in paramedicine, the identification of safety outcomes is an important first step. Safety outcomes described in the literature include paramedic injury/exposure to pathogens, medical errors/adverse events (eg, unintended extubation), and safety compromising behaviors (eg, exceeding the speed limit while driving in a non emergency). 4 The next step is to identify what factors might predict safety outcomes. For example, recent research has shown a clear link between fatigue and safety outcomes in paramedics. 4 Although an empirical link has been established between fatigue and safety outcomes, no currently published research explores how other types of workplace-related stresses and stress reactions, along with fatigue, might contribute to safety outcomes. One of the most widely studied workforce health issues is post-traumatic stress. [5][6][7][8][9][10][11][12][13] Research has linked post-traumatic pathology to errors in judgment in paramedics. 14 Further, post-traumatic stress, even at subclinical levels has been linked with functional impairment. 15,16 Given the evidence, it is reasonable to hypothesize that post-traumatic stress symptomatology (PTSS) may influence safety outcomes.
Many factors may influence the development of post-traumatic symptomatology. Extant research has linked stress reactions like posttraumatic stress to both chronic and critical incident stresses. 17,18 Chronic stresses are relatively stable and consistent over time. 19 In paramedicine, chronic stresses include operational stress (the stress of working in the field of paramedicine regardless of the service) and organizational stress (the stress associated with working in a specific paramedic service). 20 Critical incident stress refers to the stress associated with patient care. 21,22 These workplace stresses have been empirically linked to post-traumatic stress and post-traumatic stress may be linked to safety outcomes, therefore the question becomes, what influence might work-related stress have on safety?
The objective of this study was to examine the relative influence of chronic operational stress, chronic organizational stress, critical incident stress, post-traumatic stress, and fatigue on safety outcomes.

The Canadian Emergency Medical Services system
The designation and level of training for emergency medical services Paramedics in the United States. As respondents to this survey came from Advanced Life Support services, respondents were all certified at the Primary Care Paramedic level or higher. The term "paramedicine" is used in this article as it is the preferred term in the Canadian system.

Work-related stress
Two types of stress which might influence stress reactions for those in paramedicine were included. Chronic stresses were assessed using the Emergency Medical Services Chronic Stress Questionnaire (EMS-CSQ). 20 The EMS-CSQ assesses operational stress, which is the stress associated with working in EMS generally (eg, shift work, being away from family). The EMS-CSQ also assesses organizational stress, which is the stress associated with the culture in a specific paramedic service

Post-traumatic stress
PTSS is a cluster of symptoms that develop after exposure to trauma (eg, intrusive memories or flashbacks, avoidance of reminders of the event, negative alterations in cognition, alterations in arousal, and reactivity). 23 To assess post-traumatic stress, the PTSD checklist-Military (PCL-M) was used. 24 This 17-item scale has been used successfully in multiple previous studies with paramedics. 17,18 In this study, the PCL-M was changed slightly, with participants being asked about a stressful work experience rather than a stressful military experience.
The PCL-M can be summed and scored continuously, or a cutoff can be used to establish probable PTSD. Scoring recommendations vary based on the expected level of rates of PTSD; this study used a cutoff of 50 for probable PTSD, 25 which is the most conservative of the recommended cut-off scores that increases the sensitivity of the scale.

Fatigue
Fatigue, or the sense of "tiredness" that individuals experience, 26 was assessed using the Chalder Fatigue Scale. 27 This scale has been successfully used with paramedic populations in the past 28 and assesses fatigue using an 11-item scale scored on a 4-point Likert scale.
Responses are summed; a total over 4 is considered fatigued.

Safety outcomes
To assess safety outcomes, the EMS Safety Inventory was used (EMS-SI

Demographics
Respondents were asked about age, the number of years they had been in the paramedic profession, gender, marital status, level of certification, hours worked weekly, number of paramedic jobs held, ethnicity, and income.

Study protocol
This study used a cross-sectional online survey methodology.

Analysis of data
In primary analysis, respondent-level data was used for descriptive analyses and bivariate analyses. Analysis of covariance (ANCOVA) was used to assess for significant relationships between the independent variables and safety outcomes. Categorical variables were dichotomized as gender (male/female), marital status (partnered/not partnered), level of certification (Advanced Care Paramedic/Primary Care Paramedic), and ethnicity (white/visible minority). Paramedic service (the service the paramedic was employed by) was used as a covariate. Demographic characteristics that were significantly correlated with safety outcomes were also used as covariates in addition to paramedic service.
As paramedics were nested within paramedic services, hierarchical

RESULTS
Of the 54 services, 10 agreed to participate. Out of the total of 1767 paramedics in the participating regions, 825 responded to the survey; however, after removing those with <80% completion, the overall usable response rate for the survey was 40.5% (n = 717). Responses were received from paramedics at all 10 services that opted to participate in the study. Within services, response rates varied, ranging from 24%-54%. A total of 69 individuals completed the non-responder survey.

Sample demographics
Most respondents were male (66%), white (93%), and certified at the Primary Care Paramedic level (78%). The average age of respondents was 38 (SD = 10.1) and the average number of years in paramedicine was 13.6 (SD = 9.9). Respondents reported most frequently working between 41 and 60 hours (71%) and working 12-hour shifts (99%). A simple majority of respondents reported being married (57.5%), the vast majority reported working 1 job (76.5%) and 82% reported making over $70,000 per year. This sample was overwhelmingly white (92.7%).
To assess for the relative representativeness of this sample to the overall paramedic population, a review of studies of paramedics was conducted to compare demographic characteristics of this sample. The results are presented in Table 1. 17,29,30,32,33

Stress and safety
In Safety-compromising situations were reported by most respondents; 80.2% reported some sort of injury or exposure, 95.3% reported at least 1 safety compromising behavior, and 76.4% of respondents reported an adverse event or medication error. Before multivariable analyses, the demographic variables were assessed for significance with the safety variables. The results were as follows in Table 2.
Age and years in paramedicine were significantly associated with safety-compromising behaviors and errors/adverse events (P < 0.01), with younger paramedics and those with fewer years in paramedicine report reporting higher levels on both outcomes. Level of certification was significantly related to injuries/exposures (P < 0.01), safetycompromising behaviors (P < 0.001), and errors/adverse events (P < 0.001). Respondents certified at the Advanced Care Paramedic level reported higher levels of all safety outcomes than respondents at the Primary Care Paramedic level. Hours worked weekly were significantly related to injuries, (P < 0.01) and safety compromising events (P < 0.01), with those who worked more hours reporting higher rates. The more jobs individuals reported working, the more errors and adverse events were reported (P < 0.05). Given bivariate significance, these demographic variables were included in subsequent analyses as covariates. The descriptive statistics between demographics characteristics and safety outcome is included as Appendix B.
In further bivariate analysis, all the stress factors and fatigue were significantly associated with injuries/exposures, safety compromising behaviors, and errors/adverse events (P < 0.01), with a higher level of stress and fatigue reporting higher levels on the safety outcomes (Table 3).

Injuries and exposures
To test the multivariable relationships predicting injuries and expo-  (Table 4).
To further explore the effect of paramedic service and account for Model 4 allowed intercepts to vary across paramedic services, which accounted for significant variance (2.37%) in injuries and exposures and significant improvement in model fit, χ 2 change (1) = 5.683, P < 0.05. Tabled intercept value represents a fixed effect across all individuals. a Slopes and intercepts allowed for vary across paramedic services, thus negating overall effect for paramedic service. Model 5 allows for subjects to be nested across services and provides parameter estimates and SE. b Both hierarchical linear modeling and GEE do not provide R 2 statistic.
After taking the variability in intercepts into account in the GEE model,

Non-responder survey
To assess for differences among responders and non-responders (paramedics who did not respond to the survey and did not opt out of participation), a follow-up survey was undertaken. The purpose of this non-responder survey was not to query respondents about stress or safety, but to assess for demographic differences between those who responded to the survey and those who did not. A total of 69 responses were received from 9 paramedic services. No significant differences Model 4 allowed intercepts and slopes to vary across services, which produced best-fitting model. Allowing only intercepts to vary across services resulted in non-significant improvement in the fit of the model, χ 2 change (1) = 0.826, P > 0.10. Tabled intercept value represents a fixed effect across all individuals. a Slopes and intercepts allowed for vary across paramedic services, thus negating overall effect for paramedic service. Allowing interaction of slopes and intercepts resulted in significant improvement in fit, χ 2 change (1) = 5.950, P < 0.05. Model 5 allows for subjects to be nested across services and provides parameter estimates and SE. b Both hierarchical linear modeling and GEE do not provide R 2 statistic. Model 4 allowed intercepts and slopes to vary across services, which produced best-fitting model. Model 4 allowing only intercepts to vary across services resulted in non-significant improvement in the fit of the model, χ 2 change (1) = 0.458, P > 0.10. Tabled intercept value represents a fixed effect across all individuals. a Slopes and intercepts allowed for vary across paramedic services thus negating overall effect for paramedic service. Measuring variability in slopes across services, together with the interaction of slopes and intercepts, resulted in significant improvement in fit, χ 2 change (2) = 6.070, P < 0.05. Model 5 allows for subjects to be nested across services and provides parameter estimates and SE. b Both hierarchical linear modeling and GEE do not provide R 2 statistic. high as recent Canadian national study of paramedics that found a prevalence rate of 24.5%, 13 it is significantly higher than in samples of the general population, where the prevalence of PTSD is between 6.8% and 7.8%. 35,36 The first safety outcomes examined was risk for injury or exposure.

TA B L E 6 ANCOVA and hierarchical linear modeling analyses on medication errors and adverse events
In addition to fatigue, critical incident stress and PTSS were significant predictors for injury or exposure. Although work-related stress, including critical incident stress, has been tied to PTSS in previous research on paramedics, this is the first evidence that critical incident stress influences the physical safety of paramedics in addition to influencing their psychological health.
The second safety outcome, safety-compromising behaviors, was significantly influenced by critical incident stress and fatigue. Organizational stress also become influential, indicating that organizational culture has an ability to impact the safety behaviors of paramedics.
These findings serve as an extension of research that has linked perceived safety culture and safety behaviors. In the interest of improving safety for paramedics and their patients, creating change should take the form of collaborative and iterative efforts that include employer, employee, unions, and human resources.
Findings offer suggestions as to where interventions could potentially be targeted. As fatigue remains the most influential predictor of safety outcomes in this sample, implementing a fatigue management strategy may be a good first step. Guidelines are available for the management of fatigue and fatigue reduction 37 and these guidelines could be used to assist leaders to lessen the impact that fatigue plays on safety. Additionally, the fact that paramedic service was a significant predictor of safety outcomes indicates that it is an important influence on safety.
Given this finding, it may be possible to learn from "high performing" services to improve safety across all paramedic services.
Further, opportunities should be explored to focus on improving mental health fitness at both the employee and employer level. Given the influence of workplace stresses on safety, attention should be paid to mitigating these stresses. This may take the form of organized work events, anonymous feedback for system improvements, educational workshops offering practical tools to incorporate into a high stress occupation, and confidential access to mental health services. It may be impossible to fully remove all stress factors in the occupation; more work can be done to improve organizational culture and removing stress by mitigating operational conflict and scheduling issues, supporting a culture of both physical health, and mental health to better respond to stressful events, and limit injury and error.

LIMITATIONS
This study has several limitations. Paramedic services self-selected into the study, so the sample is not generalizable to the broader population. The response rate being <50% also limits the generalizability of the findings; however, it is comparable with response rates for other surveys that used online methodologies. 38 Additionally, the nonresponder survey found few significant differences between the nonresponders and the responders, and the response rate is higher than other large-scale internet-based surveys for paramedics. [39][40][41] The reliance on participant self-report creates the possibility of introducing biases including social desirability bias, 42 wherein respondents report how they would prefer to be seen rather than how they are really behaving. Further, respondents were queried about events in the past 3 months; however, there is no way to independently assess if responses are being accurately recalled, 43 introducing the possibility of recall bias. Respondents may be underreporting events because of fear of reprisal or variability in safety culture. 44,45 This study was not able to differentiate fatigue related to work versus fatigue related to out-of-work commitments and did not control for service specific events (eg, if service was in negotiations with a union or managing with an investigation).
A final limitation which perhaps might be addressed in future research is the failure to capture if stress and fatigue management services were made available and if paramedics accessed those services.
Paramedic Service retained a significant relationship to all 3 safety outcomes, which indicates there is an uncaptured difference in paramedic services which significantly influences safety. Future research may be able to improve on this research by capturing not only structural supports (eg, Employee Assistance Plans or Peer Support programs), but assessing the broader culture of safety.

ACKNOWLEDGMENTS
The authors wish to gratefully acknowledge the support of the Paramedic Chiefs of Canada and of Chief Bruce Krauter and Essex-Windsor EMS as our valued community partners in this research. We further wish to thank all the paramedic services and the paramedics for their participation.

CONFLICTS OF INTEREST
The authors declare no conflict of interest.

AUTHOR CONTRIBUTIONS
EAD takes responsibility for the paper as a whole.