The aim of the present study was to discuss the way visibility constitutes a power device in the everyday practice of the Mobile Emergency Care Service in Belo Horizonte, Minas Gerais, Brazil. A qualitative case study was developed and data were collected through semi-structured interviews with 31 workers of the service (five physicians, 11 nurses, seven nursing assistants and eight ambulance drivers) and submitted to discourse analysis. The analysis of power relations in the service allowed to verify that there is not an only one source from which the power emanates in this organizational structure. Power is exercised through many techniques and their sources are scattered, diffuse, interchangeable and even confusing. Although there is a hierarchical structure formally established, a parallel network to this structure is formed. It was also observed that the visibility generated by radio communication provides constant supervision, which generates tension within the team.
Power; Professional practice; Interpersonal relations; Emergency medical services