Background Physical restraints are used in intensive care units, particularly among patients at risk for self-terminating necessary treatment interventions, including endotracheal tubes and invasive catheters. Assessments conducted by intensive care unit nurses often influence the collaborative decision to initiate and discontinue restraints in critical care patients. However, little is known about factors that influence the critical thought processes of intensive care unit nurses in determining use of restraints. Objectives To describe nurses’ determinants of initiation and discontinuation of restraints in surgical intensive care unit patients. Methods Semistructured interviews were conducted to identify and describe determinants of initiation and discontinuation of physical restraints. Demographic and employment data were collected via questionnaire. Interviews were recorded, transcribed, and analyzed by using conventional content analysis to establish categories and identify themes. Results A total of 13 nurses (mean age 43 [SD, 12] years, 92% female, mean of 18 [SD, 12] years of practice as a registered nurse, 69% bachelor of science in nursing) participated in the study. Content analysis revealed 3 general categories and 8 themes that indicated the thoughtful reflection processes nurses in a surgical intensive care unit use to determine use of restraints. Conclusions Top priorities were ensuring patient safety and comfort. Nurses synthesized factors including practice experience, patient-specific behaviors and risk, and patients’ need for devices in determining use of restraints.