["One always has to be watchful": Categorisation of patient-related complexity of nursing care in acute care hospitals].

Background: The increase of chronic illnesses and multimorbidity as well as more challenging treatment methods have caused higher acuity and complexity of nursing care situations. Aim: The aim of this study was to explore and establish categories which describe different levels of patient-related complexity of nursing care in order to broaden the understanding of demands on nursing care due to patient situations. Methods: Using a collective case study design. we asked registered nurses and clinical nurse specialists to assess the complexity of twelve nursing care situations through a questionnaire before interviewing them about their deliberations on how they rated the situation. In this sub-study, we performed a qualitative secondary analysis of these data and looked for categories of comparable degrees of complexity. Results: We found five categories of complexity, ranging from "slightly complex" to "highly complex". "Slightly complex" situations demanded a nurse's attention on routine interventions, while "highly complex" situations demanded their constant attention on poorly assessable and poorly controllable conditions with uncertain outcomes. Conclusions: The five categories of complexity describe characteristics of the different levels of complexity in nursing care situations. They can support nursing managers with allocating nursing staff to patients according to their needs and provide a framework for discussing complex nursing care situations in basic and continuing education.