Siddik‐Sayyid 2009.

Study characteristics
Methods	RCT
Participants	183 women Inclusion criteria: non‐labouring women, > 37 weeks' gestation, ASA I or II scheduled for elective caesarean Exclusion criteria: pregnancy‐induced hypertension, chronic hypertension, multiple gestation, known fetal compromise, diabetes mellitus, polyhydramnios, weight > 100 kg, major systematic disease, anaemia (haemoglobin concentration < 10 g/dL), or clotting diathesis Setting: Lebanon
Interventions	Colloid preload versus colloid coload Group 1: colloid preload: preload of 500 mL HES (6% HES 130/0.4), administered by gravity at a wide open rate over 15‐20 min before spinal anaesthesia Group 2: colloid coload: coload of 500 mL of HES (6% HES 130/0.4) administered using a pressure infusion system at the maximum possible rate, commenced at the time of identification of CSF All women received a standardised spinal anaesthetic technique and dose, a standardised crystalloid infusion after spinal anaesthetic, and a standardised oxytocin regimen after delivery. Hypotension requiring intervention was managed with 6 mg IV bolus of ephedrine if heart rate < 90 bpm or 0.1 mg phenylephrine IV bolus if heart rate > 90 bpm.
Outcomes	Maternal: hypotension; minimum SBP; maximum heart rate; time to hypotension; ephedrine dose; phenylephrine dose; nausea and/or vomiting; metoclopramide administration; total Ringer's lactate; duration of infusion; duration of surgery; sensory block level; duration of anaesthesia Neonatal: birthweight; Apgar score; umbilical vein pH, pO2, pCO2, BE; umbilical artery pH, pO2, pCO2, BE
Notes	Hypotension was defined as the administration of at least 1 dose of vasopressor. Severe hypotension was defined as SBP < 80 mmHg.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated table of random numbers
Allocation concealment (selection bias)	Unclear risk	"Randomised" – no further details provided
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Woman, anaesthetist performing the spinal block, collecting the data and treating adverse effects, and the paediatrician assessing neonatal outcomes were all unaware of group allocation. The infusion bag was prepared and hidden behind a drape and administered by a nurse who was not involved in anaesthetic management (and who decided when the woman should sit up for spinal anaesthesia). To maintain blinding, this occurred after completion of colloid administration in the preload group (lasting ~15‐20 min) or 15‐20 min from starting the Ringer's lactate in the coload group.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	See above
Incomplete outcome data (attrition bias) All outcomes	Low risk	5/183 women were excluded after randomisation due to protocol violations (2 from the preload group and 3 from the coload group)
Selective reporting (reporting bias)	Unclear risk	Most expected outcomes reported but some (all neonatal outcomes) not reported in a form that could be used in this review (e.g. medians, and average for Apgar scores)
Other bias	Low risk	No apparent risk of other sources of bias