The aim of this study was to compare a number of potentially stress-generating factors related to an intensive care unit (ICU) stay from the points of view of patients undergoing liver transplantation or elective major abdominal surgery and their caregivers in order to identify differences and similarities that may help to optimize patient care. The ICU Environmental Stressor Scale questionnaire was administered to 104 liver transplant recipients, 103 major abdominal surgery patients, 35 nurses and 21 physicians. The ICU staff were asked to complete the questionnaire on the basis of their perception of patient stressors. Both patient groups identified Being unable to sleep, Being in pain, Having tubes in nose/mouth, Missing husband/wife, and Seeing family and friends only a few minutes a day as the major stressors; the healthcare providers correctly identified the most stressing factors for the patients, but gave them higher scores. The mean scores were 71.9 +/- 18.7 for the transplant recipients, 66.3 +/- 20.9 for the patients undergoing elective major abdominal surgery, 99.7 +/- 19.2 for the nurses, and 92.7 +/- 16.1 for the physicians (P < 0.001). The qualitative evaluations of potentially stress-inducing ICU situations were substantially the same in the 2 patient groups, but the transplant recipients seemed to feel them more acutely. Although the caregivers identified the most discomforting situations, they overestimated the degree of stress they cause. The staff of each ICU should therefore seek to understand and reduce (even by means of simple interventions) the particular causes of psychophysical stress felt by their patients.