Bouchnak 2012.

Study characteristics
Methods	RCT
Participants	60 women Inclusion criteria: ASA I scheduled for elective CS, singleton term pregnancy Exclusion criteria: chronic or gestational hypertension, cardiac disease, diabetes, known fetal abnormalities, contraindication to spinal anaesthesia Setting: Tunisia
Interventions	Colloid preload versus crystalloid preload Group 1: HES 130/0.4 500 mL preload 15 min prior to spinal anaesthesia. Group 2: saline – normal saline solution preload 1000 mL within 15 min prior to spinal anaesthesia All women received standardised anaesthetic technique and dose. Hypotension requiring intervention: 6 mg bolus ephedrine when SBP was < 80% of baseline.
Outcomes	Maternal: hypotension; SBP; adverse effects; need for ephedrine; heart rate; tachycardia (> 100 bpm); nausea; vomiting; pruritus Neonatal: umbilical blood gases; Apgar scores ar 1 min and 5 min; birthweight
Notes	Hypotension defined as SBP < 80% baseline
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Reported only as "randomized"
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not reported
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not reported
Incomplete outcome data (attrition bias) All outcomes	Low risk	Not reported
Selective reporting (reporting bias)	Unclear risk	Some outcomes not fully (numerically) reported
Other bias	Low risk	Similar baseline characteristics