Perumal 2004.

Study characteristics
Methods	RCT
Participants	40 women Inclusion criteria: healthy term women awaiting elective caesarean under spinal anaesthesia
Interventions	Colloid preload versus crystalloid preload Group 1: HES preload, 1000 mL over 15 min Group 2: Ringer's lactate preload, 1500 mL over 15 min All women received a standardised spinal anaesthetic technique and dose.
Outcomes	Maternal: hypotension; heart rate; Doppler measures; ephedrine use
Notes	Hypotension was defined as 20% reduction in SBP
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Methods not described
Allocation concealment (selection bias)	Unclear risk	Methods not described
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	"Double blind" – no further details
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	As above
Incomplete outcome data (attrition bias) All outcomes	Low risk	Losses to follow‐up: none reported but losses unlikely
Selective reporting (reporting bias)	Unclear risk	Not apparent, but not well reported
Other bias	Unclear risk	Not apparent, but not well reported