Calvache 2011.

Study characteristics
Methods	RCT
Participants	80 women Inclusion criteria: ASA I/II women aged 18‐45 years with an uncomplicated singleton pregnancy at term who were scheduled for caesarean under spinal anaesthesia Exclusion criteria: pregnancy‐induced hypertension, cardiac disease, diabetes, fetal complications and women in labour: post hoc exclusions (surgery lasting > 2 h; requirement for perioperative sedation; conversion to general anaesthesia, surgical complications such as intraoperative haemorrhage, protocol violations) Setting: Colombia
Interventions	Wedge versus supine position Group 1: wedge after intrathecal injection women were placed from the left lateral position to the supine position, with a right‐lumbar pelvic wedge (wooden, 35 cm long, 20 cm wide and with 20 degrees inclination), placed at the right posterior‐superior iliac crest and lumbar region Group 2: supine: after intrathecal injection, women were placed from the left lateral position to the supine position All women received no premedication, standardised oxygen therapy, standardised spinal anaesthetic technique and dose, and standardised crystalloid co‐load Hypotension was treated with IV boluses of ethylephrine 1 mg until hypotension was corrected. Bradycardia was treated with 0.5 mg atropine.
Outcomes	Maternal: hypotension BP; vasopressor requirements (median ethylephrine consumption); nausea; vomiting; bradycardia
Notes	Hypotension was defined as a 25% reduction in SBP from baseline. Bradycardia was defined as heart rate < 40 bpm.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated sequence
Allocation concealment (selection bias)	Unclear risk	"Randomly allocated" ... "by independent anesthetist"; no further details provided
Blinding of participants and personnel (performance bias) All outcomes	High risk	A single unblinded anaesthetist performed spinal anaesthesia, positioning of women, anaesthetic management and data collection
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Data analysis was blinded, but not mentioned if outcome assessment was blinded.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No losses to follow‐up
Selective reporting (reporting bias)	High risk	No neonatal outcomes reported
Other bias	Low risk	Similar baseline characteristics