Dyer 2004.

Study characteristics
Methods	RCT
Participants	50 women Inclusion criteria: less than 90 kg, ASA I and II, singleton pregnancy, presenting for elective caesarean under spinal anaesthesia Exclusion criteria: pre‐eclamptic women Setting: South Africa
Interventions	Crystalloid: preload versus rapid infusion Group 1: preload – modified Ringer's lactate, 20 mL/kg preload 20 min before spinal Group 2: coload – rapid infusion of an equivalent volume of modified Ringer's lactate immediately after induction of spinal All women received a standardised spinal anaesthetic technique and dose. Hypotension < 80% of baseline treated with 5 mg boluses of ephedrine; < 70% of baseline treated with 10 mg ephedrine until a return to within 80% of baseline
Outcomes	Maternal: hypotension; BP; heart rate; time to block; induction to incision times; incision to birth times; anaesthesia and surgery times; blood loss; urine output; nausea; ephedrine dose Neonatal: birthweight; Apgar scores; umbilical arterial pH; umbilical arterial base deficit
Notes	Hypotension defined as BP < 80% baseline
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"Randomly allocated" – methods not described
Allocation concealment (selection bias)	Unclear risk	"Allocation card contained within a sealed envelope"
Blinding of participants and personnel (performance bias) All outcomes	High risk	"Since there were clearly pre‐defined target MAPs for vasopressor administration for each individual, the study was not blinded"
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
Selective reporting (reporting bias)	Low risk	None apparent
Other bias	Low risk	None apparent