Mercier 2014.

Study characteristics
Methods	RCT
Participants	167 women Inclusion criteria: ASA I‐II, elective caesarean under spinal anaesthesia, aged > 18 years, weight > 60 kg and < 95 kg, term singleton pregnancy (> 37 weeks' gestation) Exclusion criteria: concomitant diseases (e.g. pregnancy‐induced hypertension, diabetes mellitus, cardiovascular or cerebrovascular disease, coagulation disorders), fetal complications, contraindications to spinal anaesthesia or HES administration, emergency CS, women who received IV fluid prior to admission to theatre Setting: multicentre, France
Interventions	Colloid versus crystalloid preload Group 1: HES: 500 mL 6% HES 130/0.4, followed by 500 mL Ringer's lactate Group 2: RL: 500 mL of Ringer's lactate, followed by second infusion of 500 mL Ringer's lactate All women received standardised aspiration prophylaxis, standardised monitoring, standardised anaesthetic technique and dose. Maternal bradycardia treated with atropine 0.5‐1 mg IV Hypotension treatment: SBP > 95% baseline – no treatment, SBP 94‐80% baseline received 50 μg phenylephrine, SBP 79%‐90% of baseline received 100 μg phenylephrine, SBP < 70% of baseline received 150 μg phenylephrine. Sustained nausea and vomiting was treated with ondansetron 4 mg IV.
Outcomes	Maternal: incidence of hypotension; time of onset of hypotension; symptomatic hypotension; nausea and vomiting; dizziness; minimum heart rate; bradycardia; atropine and phenylephrine requirement Neonatal: Apgar scores at 1 min and 5 min, umbilical arterial and venous pH
Notes	Hypotension defined as SBP < 80% of baseline Bradycardia defined as heart rate < 50 bpm
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated randomisation sequence using SAS software; blocks of 4
Allocation concealment (selection bias)	Unclear risk	Not mentioned
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐blind: "study fluids were provided in indistinguishable 500 mL bottles in both groups with randomisation code, as previously pictured."
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Double‐blind
Incomplete outcome data (attrition bias) All outcomes	Low risk	Clearly reported in study results 11 protocol violations in HES group, and 10 in the Ringer's group Intention‐to‐treat analysis
Selective reporting (reporting bias)	Low risk	Not apparent
Other bias	High risk	Fully funded by Fresenius Kabi, the company that produces HES