- Design
- Secondary analysis of a prospective international observational cohort
- Population
- 5,664 invasively ventilated patients; 4,394 with at least one separation attempt, of whom 664 failed weaning at day 90
- Primary outcome
- ICU mortality
- Effect
- 78% ICU mortality in failed-wean versus 2% in successful-wean; three failed-wean phenotypes defined by separation attempt count and timing of withdrawal decisions
This secondary analysis of WEAN SAFE followed 5,664 ventilated patients. Of those who reached at least one separation attempt, 664 (15.1%) had still failed to wean at day 90 and 3,730 (65.9%) succeeded. A further 1,270 (22.4%) never had a separation attempt at all.
The outcome gap is stark: ICU mortality was 78% in the failed-wean group against 2% in those who weaned. Failed-wean patients had the longest ventilation and the longest ICU stay, underwent more separation attempts but fewer attempted extubations, and had more reintubations and tracheostomies.
Three phenotypes emerged, distinguished by how many separation attempts occurred and when life-sustaining therapy was withdrawn or withheld: a single attempt followed by withdrawal, a single attempt without withdrawal, and more than one attempt. A failed first separation attempt was strongly associated with the decision to withdraw. The authors flag, correctly, that this relationship needs investigating rather than interpreting — a first failed attempt may identify a patient who was always going to die, or it may be the moment at which a team's expectations change and the trajectory follows.
- Treat a failed first separation attempt as a prompt to reassess reversible contributors — sedation, fluid balance, diaphragm function, delirium, nutrition — not as prognostic information.
- Note the 22.4% who never had a separation attempt at all; a daily readiness assessment is what stops a patient joining that group by default.
- Distinguish failing a spontaneous breathing trial from not being extubated — the failed-wean group had more attempts but fewer extubations.
- Document explicitly what changed after a failed attempt and what the plan is for the next one.
- Where withdrawal is being considered, separate the prognostic judgement from the weaning result and make the reasoning visible.
Why it matters
The first failed spontaneous breathing trial may be doing more prognostic work in a team's mind than the evidence supports.
Don't overread it
This is an observational secondary analysis; the link between a failed first attempt and death cannot be read as causal.
The statistics, in plain English
A 78% versus 2% mortality difference is not a treatment effect — it is the difference between two groups defined partly by their outcome, since failing to wean by day 90 and dying in ICU are closely intertwined. The association between a failed first attempt and withdrawal of life-sustaining therapy is the finding with real content, and it is the one most vulnerable to reverse causation: the decision may follow the clinical picture, or shape it.
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