Carvalho 2009.
| Study characteristics | ||
| Methods | RCT | |
| Participants | 46 women Inclusion criteria: women scheduled for caesarean under spinal anaesthesia; age 18‐54 years; weight ≤ 100 kg; height ≥ 150 cm; ASA physical status I or II; uncomplicated term pregnancy Exclusion criteria: pregnancy‐induced hypertension; cardiac disease; diabetes or fetal complications; women in labour Setting: USA |
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| Interventions |
Colloid preloading versus colloid coloading Group 1: colloid preload: 500 mL 6% hetastarch IV slowly over 20 min before spinal anaesthesia Group 2: colloid coload: 500 mL 6% hetastarch IV as quickly as possible, with the aid of a pressure bag, immediately after spinal anaesthesia All women received standardised aspiration prophylaxis and standardised spinal anaesthetic technique and dose. Hypotension requiring intervention was managed with vasopressor mix of 5 mg/mL ephedrine plus 25 μg/mL phenylephrine given according to a strict predefined algorithm (systolic pressure ≥ 90% of baseline: no vasopressor; 80%‐89% systolic pressure: 1 mL equivalent to ephedrine 5 mg + phenylephrine 25 μg; 79%‐79% systolic pressure: 2 mL equivalent to ephedrine 10 mg + phenylephrine 50 μg; systolic pressure < 70%: 3 mL equivalent to ephedrine 15 mg + phenylephrine 75 μg) |
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| Outcomes |
Maternal: hypotension; bradycardia; tachycardia; nausea, vomiting; total vasopressor dose Neonatal: umbilical and venous arterial pH; Apgar scores; neonatal weight |
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| Notes | Hypotension defined as SBP < 90% baseline Bradycardia defined as heart rate < 40 bpm Tachycardia defined as heart rate > 140 bpm |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Random numbers generated using MS Excel |
| Allocation concealment (selection bias) | Unclear risk | Sealed, opaque envelopes |
| Blinding of participants and personnel (performance bias) All outcomes | High risk | Not feasible to blind the interventions |
| Blinding of outcome assessment (detection bias) All outcomes | Unclear risk | Not reported |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | No losses to follow‐up |
| Selective reporting (reporting bias) | Unclear risk | Most expected outcomes were reported, although some were reported in a form that could not used in this review |
| Other bias | Low risk | Similar baseline characteristics |