Defining best practice for very old patients following unplanned intensive care admission: protocol of the Delphi consensus study

Very old patients (≥80 years) represent a rapidly increasing proportion of intensive care unit (ICU) admissions across Australia and New Zealand. Care of this population is characterised by substantial prognostic uncertainty and variability in ICU triage, treatment limitation and post-ICU pathways. In particular, the role and implementation of time-limited ICU trials remain inconsistent.

To establish multidisciplinary consensus on best-practice management of very old patients following unplanned ICU admission in Australia and New Zealand, including the role, structure and implementation of time-limited ICU trials.

We will conduct a modified, multiround Delphi consensus study. A multidisciplinary, multispecialty panel of expert clinicians (intensive care, geriatrics, emergency medicine), doctors in training, nurses, allied health professionals, ethicists and health service leaders across Australia and New Zealand will be recruited through purposive and snowball sampling. Participants will rate statements using the Likert scale across multiple rounds. Anonymised aggregated feedback will be provided to participants between rounds to facilitate convergence of opinion. Consensus will be defined a priori using predefined thresholds and median scores. Quantitative analyses will include descriptive statistics and exploratory subgroup comparisons, while free-text responses will undergo thematic analysis.

The primary outcome is to establish multidisciplinary consensus on best-practice management of very old patients following unplanned ICU admission, including the role and implementation of time-limited ICU trials. Secondary outcomes include identifying areas of agreement and variation across groups and convergence across Delphi rounds. A tertiary outcome is to explore barriers and facilitators to implementation to inform a structured decision-making framework.

This study will generate consensus-based recommendations and a structured framework for the use of time-limited ICU trials in Australia and New Zealand ICUs. By addressing current practice variability, it aims to support transparent, patient-centred decision-making and inform future research and policy in the care of very old critically ill patients.