Optimising time-limited trials in acute respiratory failure: a multicentre focused ethnography protocol

The 'time-limited trial' for patients with critical illness is a collaborative plan made by clinicians, patients and families to use life-sustaining therapies for a defined duration. After this period, the patient's response to therapy informs decisions about continuing recovery-focused care or transitioning to comfort-focused care. The promise of time-limited trials to help navigate the uncertain limits and benefits of life-sustaining therapies has been extensively discussed in the palliative and critical care literature, leading to their dissemination into clinical practice. However, we have little evidence to guide clinicians in how to conduct time-limited trials, leading to substantial variation in how and why they are currently used. The overall purpose of this study is to characterise the features of an optimal time-limited trial through a rich understanding of how they are currently shaping critical care delivery.

We are conducting an observational, multicentre, focused ethnography of time-limited trials in patients with acute respiratory failure receiving invasive mechanical ventilation in six intensive care units (ICUs) within five hospitals across the US. Study participants include patients, their surrogate decision makers and ICU clinicians. We are pursuing two complementary analyses of this rich data set using the open-ended, inductive approach of constructivist grounded theory and, in parallel, the structured, deductive methods of systems engineering. This cross-disciplinary, tailored approach intentionally preserves the tension between time-limited trials' conceptual formulation and their heterogeneous, real-world use.

This study has been reviewed and approved by the University of Wisconsin Institutional Review Board (IRB) as the single IRB (ID: 2022-1681; initial approval date 23 January 2023). Our findings will be disseminated through peer-reviewed publication, conference presentations, and summaries for the public.

NCT06042621.