Quality of life in intensive care unit survivors—Family member dyads. A conceptual framework and longitudinal study protocol

Background: Critical illness threatens the Quality of Life (QoL) of both ICU survivors and their family members through Post-Intensive Care Syndrome (PICS) and its family counterpart (PICS-F). These syndromes unfold within the ICU survivor-family member dyad, yet their dyadic interdependence and joint trajectories remain insufficiently explored. Aim: To develop a conceptual framework and study protocol for a longitudinal investigation of dyadic QoL in ICU survivor-family member dyads, with explicit attention to reciprocal interdependence over time. Design and methods: A longitudinal study will enrol ICU survivor-family member dyads assessed at 1, 3, 6 and 12 months post-ICU discharge in two Italian ICUs. The 1-month timepoint captures early PICS and PICS-F manifestations while minimising post-discharge confounding. A qualitative phenomenological component will explore how survivorship is experienced within the dyad. Dyadic QoL trajectories will be examined using descriptive statistics, χ2 tests, Student's t-tests and Mann-Whitney U-tests. Longitudinal analyses will apply hierarchical linear models to capture trajectories over time. Qualitative data will be analysed manually following Cohen's hermeneutic phenomenological approach. Conclusion: This protocol advances the conceptualisation of post-ICU outcomes as dyadic and interdependent, integrating quantitative and qualitative evidence within a relational framework. Relevance to clinical practice: Findings will inform nurse-led follow-up interventions targeting ICU survivors and family members as an interdependent unit, supporting person- and family-centred care across the post-ICU trajectory.