This study assesses the ergonomic quality of a new writing format used for the written transmission of activity during a nurse’s handover in a hospital. This format called “targeted or focussed transmission” comes from a new prescription of hospital management designed to improve the written handover process. Our research focused on the information filtering process for each patient concerned by a shift handover. A three step methodology was designed, with the participation of 9 nurses in charge of 70 patients: (1) nursing work analysis before the handover, (2) oral handover analysis, (3) written handover analysis. Results show that the new writing format does not match the nurses’ needs to perform high quality handovers. The main clues, clinical signs and patient behaviour, used by nurses during an oral handover, to supervise the monitoring of the patient state disappear from the content of the written handover document. Regulation activities carried out to manage areas of dysfunction within the patient’s state, which are a main topic in the oral handover, are not included in the written handover document. The different roles played by oral dialogue and written traces in the patient monitoring activity have been analysed and discussed. Finally, a cognitive model of professional written production is proposed and discussed and also some recommendations to design writing tools for the optimization of written handover documents.