Le Bourdelles 1996.

Methods	Randomized cross‐over study comparing HME to HH.
Participants	Inclusion criteria: people receiving inspiratory pressure support during weaning trials from mechanical ventilation. Mean age: 63 years. Exclusion criteria: not stated. Respiratory diagnosis: 53%. Mean SAPS score: 16. Setting: hospital, France.
Interventions	HME (hygroscopic): Hygrobac (DAR). n = 15. HH: MR450 (Fisher & Paykel). n = 15. Time in study: 20 min.
Outcomes	Tidal volume. Minute ventilation. PaO2. PaCO2. Respiratory rate.
Notes	Funding: not stated.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not stated.
Allocation concealment (selection bias)	Unclear risk	Not stated.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not stated.
Incomplete outcome data (attrition bias) All outcomes	Low risk	100% follow‐up.
Selective reporting (reporting bias)	Low risk	No protocol available but a range of respiratory variables reported for this short‐term study.
Other bias	Low risk	None identified.