Interpreting an ICU trial for practice change — FFICM MCQ

Correct answer: C — Assess external validity and baseline practice before changing the unit protocol

The correct answer is C, assess external validity and baseline practice before changing the unit protocol. A statistically significant single-centre result with a surrogate outcome (ventilator days) and no change in mortality or delirium requires critical appraisal of applicability, not automatic adoption. The trial's control arm used unusually deep sedation and different nurse staffing, both of which threaten external validity: your unit already runs daily sedation targets and spontaneous awakening trials, so the comparator gap that generated the benefit may not exist locally. Good evidence-based practice means weighing population, comparator, co-interventions and current baseline performance before altering established protocols, exactly as emphasised in critical appraisal teaching for intensive care trainees. Since your baseline sedation practice already approximates the intervention arm, the incremental benefit demonstrated may simply not be reproducible in your setting. Why the other options are wrong: E. Adopt the protocol immediately because p is below 0.05: statistical significance (p=0.04) reflects the probability the result is not due to chance, it says nothing about clinical relevance, generalisability, or whether the comparator conditions apply to your unit. D. Reject the study because mortality is unchanged: ventilator days is a valid and clinically meaningful secondary endpoint; trials are frequently underpowered for mortality, so an unchanged mortality signal does not invalidate the finding, it simply means the study cannot claim a mortality benefit. B. Change practice based on the abstract alone: abstracts omit methodological detail needed to judge risk of bias, comparator fidelity and generalisability; full appraisal of methods is mandatory before any practice change. A. Apply it to patients who died in the trial: this is a nonsensical post hoc subgroup approach with no biological or statistical rationale and represents a clear appraisal error, not a management strategy. Key point: A significant single-centre trial with a weak comparator and outcome mismatch to your existing baseline practice demands critical appraisal of external validity before any protocol change.

Reference: Faculty of Intensive Care Medicine, CCT in Intensive Care Medicine Curriculum (2021), domain on evidence-based practice and critical appraisal of trial applicability, https://www.ficm.ac.uk/traininginintensivecaremedicine/curriculum