Raphaël 1997c.

Methods	RCT, multicentre, open, parallel groups
Participants	N = 161, acute GBS only Adults only Severe (mechanically ventilated) forms
Interventions	4 plasma exchange versus 6 plasma exchange 3 litres per plasma exchange, diluted albumin + gelatin, plasma exchange every other day
Outcomes	Time to recover walking with assistance
Notes	‐
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer generated
Allocation concealment (selection bias)	Low risk	Centralisation of randomisation
Blinding (performance bias and detection bias) All outcomes	High risk	Non‐blinded trial, nevertheless the authors used a centralised review of case reports
Incomplete outcome data (attrition bias) All outcomes	Low risk	No loss to follow‐up, intention‐to‐treat analysis
Selective reporting (reporting bias)	Low risk	Data reported for all pre‐specified outcomes
Other bias	Low risk	Explicit diagnostic criteria, explicit outcome criteria, no imbalance in baseline characteristics between treatment arms

GBS: Guillain‐Barré syndrome; RCT: randomised controlled trial.