[Readmission to the intensive care unit : A rare phenomenon or relevant to clinical practice?]

Unplanned intensive care unit (ICU) readmissions are infrequent but clinically highly relevant. Despite their clinical importance, the underlying risk factors and mechanisms leading to unplanned readmissions remain insufficiently characterized.

This narrative review aims to summarize the current evidence on unplanned ICU readmissions, identify associated risk factors and causes, and contextualize their relevance for mortality and resource utilization.

A systematic literature search was conducted in PubMed and CINAHL. Publications in English or German published within the past 5 years were included to reflect the current state of evidence. Eligible studies investigated unplanned ICU readmissions of adult patients during the same hospital admission. Nine retrospective cohort studies were identified and narratively synthesized due to methodological heterogeneity.

Reported ICU readmission rates ranged from 3.6% to 9.1%. The included studies predominantly investigated patient populations treated at university-affiliated centers and acute care hospitals with interdisciplinary or specialized ICUs. ICU readmissions were consistently associated with increased hospital and ICU mortality, as well as prolonged hospital and ICU length of stay. Relevant risk factors included advanced age, functional impairment, cognitive disturbances, persistent organ dysfunction, and prolonged organ support. The most common causes of readmission were respiratory complications, followed by hemodynamic instability and infectious or neurological deterioration.

Unplanned ICU readmissions are infrequent but clinically highly relevant. They reflect a complex interaction of patient vulnerability, disease severity, and care-related factors, and are associated with increased mortality.