Critical care nurses work in an environment rich in informative interactions. Although there have been post hoc self-report survey studies of nurses' information seeking, there have been no observational studies of the patterns and content of their on-duty information behavior. This study used participant observation and in-context interviews to describe 50 hours of the observable information behavior of a representative sample of critical care nurses in a 20-bed critical care hospital unit. The researcher used open, in vivo, and axial coding to develop a grounded theory model of their consistent pattern of multimedia interactions. The resulting Nurse's Patient-Chart Cycle describes nurses' activities during the shift as centering on a regular alternation with the patient and the patient's chart (various record systems), clearly bounded with nursing "report" interactions at the beginning and the end of the shift. The nurses' demeanor markedly changed between interactions with the chart and interactions with the patient. Other informative interactions were observed with other health care workers and the patient's family, friends and visitors. The nurses' information seeking was centered on the patient. They mostly sought information from people, the patient record and other digital systems. They acted on or passed on most of the information …