King 1998.

Study characteristics
Methods	RCT
Participants	30 women Inclusion criteria: undergoing elective CS Exclusion criteria: hypertension, pre‐eclampsia, preterm labour, juvenile diabetes, cocaine and methamphetamine use and cardiac disease
Interventions	Ephedrine versus ephedrine + crystalloid versus crystalloid Group 1: ephedrine infusion group: 10 mL saline bolus followed by ephedrine infusion 1 mg/mL, i.e. 20 mg in 12 min Group 2: ephedrine bolus group: 10 mg ephedrine followed by saline infusion 5 mL/min for 2 min followed by 1 mL/min for 10 min Group 3: saline bolus 2 mL followed by infusion 5 mL/min for 2 min followed by 1 mL/min for 10 min All women received a standardised crystalloid preload followed by standardised infusion, a standardised spinal anaesthetic technique and dose and standardised positioning.
Outcomes	Maternal: hypotension; time to first ephedrine rescue dose; number of hypotensive participants; total ephedrine dose Neonatal: Apgar scores at 1 min and 5 min
Notes	Hypotension was defined as SBP < 80% baseline
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method not described
Allocation concealment (selection bias)	Low risk	Adequate: study drugs prepared by a third party (pharmacy)
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Blinding: anaesthetist blinded to interventions
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	As above
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Losses to follow‐up: not stated
Selective reporting (reporting bias)	Low risk	None apparent
Other bias	Low risk	None apparent