Respiratory failure & ventilation
Evaluating the generalisability of formulas used to set tidal volumes in mechanically ventilated patients: an observational, multicohort, retrospective study
Main finding · Mortality per 1 SD increase in PBW:PFVC ratioResult — go to the resultOdds of death (per 1 SD increase in PBW:PFVC) 1.43 95% CI 1.17–1.76Authors' conclusion
Adjusting VT using PBW formulas leads to overestimation of preinjury tidal lung volumes in patients who are older, shorter, female, and non-White compared with other patients.
Study context
- Population
- Mechanically ventilated patients with lung-protective ventilation, hypoxaemia, and height 150–210 cm, from publicly available deidentified datasetstwo cohorts
- Participants
- 9,152 vs 12,420
- Exposure
- ARMA predicted bodyweight (PBW) vs predicted forced vital capacity (PFVC) as proxy for preinjury lung volume
- Medical Information Mart for Intensive Care-IV (MIMIC-IV)n = 9,152
- Electronic Intensive Care Unit Collaborative Research Database (eICU-CRD)n = 12,420
- Outcome
- Association of normalised VT (per PBW or per PFVC) and PBW:PFVC ratio with mortality, driving pressure, and normalised elastance (VT per PBW 6-8 mL/kg)
Methodological detailsobservational, multicohort
- Observational
- Multicohort
Main finding
Mortality per 1 SD increase in PBW:PFVC ratio
Odds of death (per 1 SD increase in PBW:PFVC)
1.43
95% CI 1.17–1.76
MIMIC-IV
odds of death (per 1 SD increase in PBW:PFVC) 1.43 (95% CI 1.17–1.76)
Per 1 SD increase in PBW:PFVC ratio, as printed
As reported in the abstract
Observational data: associations, not effects.
Original publication
Evaluating the generalisability of formulas used to set tidal volumes in mechanically ventilated patients: an observational, multicohort, retrospective study. Lancet Respir Med. Published 15 July 2025. doi:10.
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