Introduction

Nurses fulfill an essential role within the intensive care unit (ICU) team. They contribute to improved clinical outcomes, fewer complications as well as errors and hence to reduced morbidity and mortality. ICU nurses co-operate closely with physicians as well as with colleagues and interact with the family of the patient (Blot et al., 2011, 2014; Brock et al., 2013; Coburn and Gage-Croll, 2011; Courtenay et al., 2013; Liu et al., 2015). These collaborations can lead to ethical conflicts, in particular when nurses feel insufficiently involved in medical decisions (Falco-Pegueroles et al., 2016). ICU nurses have unique working conditions, characterised by a high technical environment and the continuous handling of seriously ill patients requiring highly specialised training and education (Endacott et al., 2015). In this regard, the ICU differs from many other departments (Cartledge, 2001; van Dam et al., 2013). The specific working conditions of ICU nurses render them vulnerable for burnout. Similar to nurses in other departments, night shifts, work-related stress, the number of days off, conflicts with colleagues or patients, the relationship with their supervisors and the organisation influence the risk on burnout among ICU nurses. For nursing staff, poorly organised services are associated with higher stress levels. Stress triggers burnout, moderated by the way nurses cope with stressors (Cartledge, 2001; Embriaco et al., 2007; Ntantana et al., 2017; Ramirez et al., 1996; Vifladt et al., 2016). Besides overall stress, anxiety and depressive symptoms seems to play a role as well. In a survey among 370 ICU nurses and 121 general ward nurses, Mealer et al. (2007) found anxiety and depressive symptoms to be common in both groups. ICU nurses, however, had an increased prevalence of post-traumatic stress disorder (PTSD) symptoms as compared with general ward nurses (Mealer et al., 2007). The experience of stress has been repeatedly demonstrated as a major determinant for burnout (Embriaco et al., 2007; McHugh et al., 2011). Burnout has a negative impact on mental health, especially when resilience is low (Arrogante and Aparicio-Zaldivar, 2017). Burnout reduces the quality of ICU team communication, leading to lower quality of care (Galletta et al., 2016). In addition, staff rotation and absenteeism become significantly more common inflicting higher costs to health care organisations (Cartledge, 2001; Embriaco et al., 2007). Besides the risk for burnout, stress and poor job satisfaction also contribute to increased turnover intention among ICU nurses. Factors associated with the intention to leave the ICU include high workload, stress-related health problems and night shifts (Cartledge, 2001; Courtenay et al., 2013; Embriaco et al., 2007; van Dam et al., 2013). The issues of burnout, absenteeism and turnover intention also have important socio-economic consequences as it threatens the availability of ICU nurses (Dessy, 2009; Embriaco et al., 2007). The key issue in these challenges is job satisfaction. High levels of job satisfaction are associated with lower intention to leave, burnout, and absenteeism among health care staff (Castle et al., 2007; Gardulf et al., 2008).