Fox 1993.

Methods	Study design: cross‐over RCT Study time frame: not stated Duration of follow‐up: one dialysis session
Participants	Country: USA Setting: single centre Stable patients on chronic HD; consent to participate in the study Mean time on dialysis: 54 months Number: 9 patients Mean age ± SD: 63 ± 4 years Sex (M/F): all male Exclusion criteria: not stated
Interventions	Treatment group HF QB: 400 mL/min Exchange volume: 1/3 of body weight Duration: one session Control group HD QB: 250 to 300 mL/min QD: 600 mL/min Duration: one session Co‐interventions: not stated
Outcomes	BP Hypotensive episodes (systolic BP < 100 mm Hg)
Notes	Exclusions post randomisation but pre‐intervention: not stated Stop or end point/s: not stated Additional data requested from authors: method of randomisation and details regarding blinding Funding: not stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	"by coin toss", an insecure method
Allocation concealment (selection bias)	Unclear risk	Not stated
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not stated
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not stated
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Insufficient data; no loss to follow‐up
Selective reporting (reporting bias)	High risk	Data for end of first phase of treatment not available, no protocol of the study available
Other bias	High risk	Carry over effect present because of the cross‐over design; data not extractable for meta‐analysis