[Complexity of care: meanings and interpretation].

Introduction: Although the concept of complexity of care is widely used and discussed, its meaning is blurred and its characteristics are not well defined.

Aims: To identify the words used to define the concept of complexity in the literature and its meaning.

Method: A literature search was performed on the following databases: Pubmed, Medline, Ebsco, Cinahl and Cochrane. No temporal limits were set; publications written in English and Italian were included.

Results: Several terms are used to define the concept of complexity, often interchangeably notwithstanding their different meaning. Three main concepts were identified: nursing intensity that includes the concepts of dependency, severity and complexity of patients care; nursing workload that comprises the concept of nursing intensity and all the activities not patient-related; and the patient acuity that includes the severity of illness and the caring intensity.

Conclusions: A common definition is needed to be able to use the concept of complexity of care to allocate nursing resources.