Van Kuijk 1996.

Methods	Study design: cross‐over RCT Duration of study: not reported Duration of follow‐up: 1 HD session analysed
Participants	Country: the Netherlands Setting: single centre Prevalent outpatients on HD (age criteria not reported), "haemodynamically stable patients who rarely suffered from intradialytic hypotension" Number: 9 patients allocated to control and then treatment, or treatment and then control, no attrition Mean age (range): 46 years (23 to 71) sex (M/F): 8/1 Mean time on dialysis (range): 46 months (12 to 53) Exclusion criteria: severe coronary (NYHA II or more) or valvular heart disease; compromised left ventricular function (ejection fraction 30% or less); diabetes mellitus
Interventions	HD regimen 2 hours/session of treatment/control Low‐flux hemophan dialyser Bicarbonate buffer QB 250 mL/min, QD 500 mL/min URR not reported Treatment group Dialysate [Na+]: 134 mM over a single HD session Control group Dialysate [Na+]: 144 mM over a single HD session Duration A single HD treatment, assessed over the first 2 hours of HD under the condition of 1 L/hour UF, treatment and control sessions separated by an unreported length of time
Outcomes	Outcomes assessed over one HD session Forearm venous tone Forearm vascular resistance Relative blood volume Predialysis SBP Predialysis DBP Postdialysis MAP Postdialysis SBP Postdialysis DBP Postdialysis MAP Predialysis serum [Na+] Postdialysis serum [Na+] PGE2 Intradialytic hypotension
Notes	Funding source: Gambro AB Because the study treatment was a single session separated by a week, predialysis study data were not included in meta‐analyses (they were not subject to the study treatment)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation clearly stated in published article, but not mechanism of randomisation
Allocation concealment (selection bias)	Unclear risk	Insufficient information to permit judgement
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Insufficient information to permit judgement
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Insufficient information to permit judgement
Incomplete outcome data (attrition bias) All outcomes	Low risk	The study appears to be free of attrition bias
Selective reporting (reporting bias)	Low risk	The study appears to be free of reporting bias
Other bias	Unclear risk	Is a study of treatment over a single truncated dialysis session with fixed UF, and the effect size attributable to the treatment is likely to be attenuated Uncertain washout

BP ‐ blood pressure; CrCl ‐ creatinine clearance; CU ‐ cuprammonium cellulose; DBP ‐ diastolic BP; EDD ‐ end‐diastolic diameter; ESD ‐ end‐systolic diameter; Hb ‐ haemoglobin; HCT ‐ haematocrit; HD ‐ haemodialysis; HRQoL ‐ health‐related quality of life; IDWG ‐ interdialytic weight gain; IQR ‐ interquartile range; Kt/V ‐ dialyser clearance adequacy; LVMI ‐ left ventricular mass index; M/F ‐ male female; MAP ‐ mean arterial pressure; MI ‐ myocardial infarction; NYHA ‐ New York Heart Association; PAN ‐ polyacrylonitrile membrane; PWT ‐ posterior wall thickness; PWV ‐ pulse wave velocity; QB ‐ blood (pump) flow rate; QD ‐ dialysate flow rate; RCT ‐ randomised controlled trial; SBP ‐ systolic BP; SD ‐ standard deviation; SEM ‐ standard error of the mean; SQRT ‐ square root; SWT ‐ septal wall thickness; UF ‐ ultrafiltration; URR ‐ urea reduction ratio; UTI ‐ urinary tract infection; VAS ‐ visual analogue scale