Hwang 2012.
| Study characteristics | ||
| Methods | RCT | |
| Participants | 86 women Inclusion criteria: elective CS Exclusion criteria: pre‐existing hypertension, pre‐eclampsia, cardiovascular disease, diabetes, obesity, multiple pregnancy Setting: South Korea |
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| Interventions |
(R) lateral positioning versus wedged supine positioning Group 1: maintain the right lateral position for 6 min after spinal anaesthesia before assuming the wedged supine position Group 2: assumed the wedged supine position immediately after the spinal injection Wedging positioning was achieved with an air balloon (1500 mL) was inserted under the right upper buttock in the supine position in both groups. All women received standardised cannulation, standardised crystalloid preload, standardised oxygen therapy and standardised spinal anaesthetic technique and dose. Ephedrine was given if BP decreased > 30% from baseline ("severe hypotension") with increments of 5 mg at 2 min intervals |
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| Outcomes |
Maternal: hypotension, nausea and vomiting, ephedrine requirement, maximum block height Neonatal: Apgar scores at 1 min and 5 min after birth, umbilical arterial blood gas analysis |
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| Notes | Hypotension defined as a decrease in MAP of > 20% from baseline Severe hypotension defined as a decrease in MAP of > 30% from baseline |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Block randomisation (6 subjects per block) |
| Allocation concealment (selection bias) | Low risk | Opaque covers – removed immediately after intrathecal injection |
| Blinding of participants and personnel (performance bias) All outcomes | Low risk | Unable to blind due to different positions but unlikely to affect observation |
| Blinding of outcome assessment (detection bias) All outcomes | Low risk | Women were in different positions for 6 minutes therefore assessor was unblinded. After the women were put in the supine position, another observer who was blinded to patient group recorded the measurements. |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | Group 1: 1 excluded due to hypertension at baseline Group 2: 1 excluded due to inadequate block Excluded women not analysed in final results |
| Selective reporting (reporting bias) | Low risk | None apparent |
| Other bias | Low risk | None apparent |