English: Stress factors for patients undergoing cardiac surgery. Español: Factores estresantes para el paciente sometido a cirugía cardíaca. Português: Fatores estressantes para o paciente submetido a cirurgia cardíaca.

Objective. To describe the stress factors related to cardiac surgery and to the environment in an Intensive Care Unit (ICU). Methodology. Exploratory, descriptive and qualitative study based on the statements of patients undergoing cardiac surgery. The data was collected through semi-structured interviews and reviewed using thematic content analysis. Results . Four categories emerged: 1) Surgical experience: overcoming fear; 2) the ICU environment and the postoperative period: a difficult experience; 3) unpleasant experiences: thirst, intubation and pain; and 4) relationship with health care professionals: impersonality, professional presence representing safety and comfort, orientation and information representing safety and clarification. Conclusion. Two groups of stress factors were identified: the intra personal (thirst, pain and others) and extra personal related to the environment. Key words: thoracic surgery; postoperative period; stress, psychological; intensive care units.