Background: Work is a determinant of employee health, and the same conditions that contribute to an illness do not favour return to work; consequently, they hinder job retention, other employees can become ill and new leaves are generated.
Objective: To analyse the nursing technicians work in intensive and semi-intensive care units (ICUs and SICUs) and discuss the influence of organisational and relational factors on return to work and job retention. This study also discusses the contributions of activity ergonomics to these processes.
Method: Qualitative case study based on ergonomic work analysis (EWA). Data were collected using documentary analyses, and global, systematic, and participant observations involving nursing technicians working in ICUs and SICUs.
Results: Task planning and the staff size adjustment to respond to the work demands of these units were ineffective in real-world situations and were aggravated by cases of absenteeism, medical leave, and employees returning to work.
Conclusions: Work structure limits return to work and job retention. An EWA based on the activities developed by professionals is a valid tool for understanding working processes by applying transforming actions to real-world work situations.
Keywords: Emergency services; ergonomics; job security; vocational rehabilitation.