Walsh 1983.

Methods	Design: randomized controlled study Withdrawals: 0 Setting: single centre, UK Sample size: 21
Participants	3 arms included in the trial, with 7 participants in each. Arms were given lactated Ringer's solution, 5% dextrose, and normal saline. Only 2 arms were included for analysis (N = 14). Age (mean): Hartmann's 55/normal saline 50 years Gender (M/F): not reported ASA grade: not reported Surgery type: elective cholecystectomy Surgery duration (mean): not reported Anaesthesia type: general
Interventions	Intervention n = 7 Buffered arm ‐ Hartmann's solution Control n = 7 Non‐buffered arm ‐ normal saline 6 mL/kg/h Co‐interventions: none
Outcomes	Estimated blood loss measured intraoperatively
Notes	Funding source: not disclosed Declarations of interest: none disclosed
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Methods of randomization unclear
Allocation concealment (selection bias)	High risk	Allocation concealment not mentioned
Blinding of participants and personnel (performance bias) All outcomes	High risk	Blinding not mentioned
Blinding of outcome assessment (detection bias) All outcomes	High risk	Blinding not mentioned
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No withdrawals
Selective reporting (reporting bias)	Low risk	No evidence of selection bias. All proposed outcome measures adequately reported
Other bias	Low risk	No other information given