Combined spinal-epidural versus epidural analgesia in labour

Regional analgesia has been shown to be effective in providing pain relief in labour. Regional analgesia can be an epidural, a spinal or a combination of the two. An epidural is when the pain-relieving drugs are injected into the part of the body which surrounds the spinal column (epidural space). It is most common for these drugs to be infused through a very fine tube (catheter) positioned in the epidural space. Traditionally, high concentrations of local anaesthetic drugs were used. These numbed the woman from the waist downwards giving pain relief for most women. However, it also caused leg weakness, poor mobility and difficulty for the mother giving birth. This led to increased instrumental vaginal births with subsequent increased bruising, pain and incontinence later on for the mother. More recently with epidurals, low-dose local anaesthetic drugs have been used in combination with opioid drugs. Here there is less numbing of the woman's legs but the opioid drugs cross the placenta and may make the baby sleepy.

A spinal is when the analgesic drugs are injected directly into the fluid surrounding the nerves in the spinal column and is quicker to take effect than an epidural. However, because a single spinal injection is only effective for a short period of time, they are not commonly used on their own for pain relief in labour. Also, the use of very fine catheters in the spinal space has been associated with increased injury to nerves. Hence, the combination of a single spinal injection combined with the use of an epidural catheter for ongoing pain relief was developed. This combined spinal-epidural was thought to have the benefits of being quicker to provide pain relief but with no change to the incidence or severity of side effects for the mother or baby.

This review of trials compared CSE with traditional and with low-dose epidurals. There were 27 trials, involving 3274 women. The data showed no difference in the mothers' satisfaction between CSE and epidurals. However, CSEs had a slightly faster onset of effective pain relief, but more women itched than with low-dose epidurals. There was no difference seen for mobility in labour, headaches, caesarean section or adverse effects for the baby. Any differences for rare complications such as nerve injury and meningitis remain unknown. There appears to be little difference overall between these techniques.

Authors' conclusions: 

There appears to be little basis for offering CSE over epidurals in labour, with no difference in overall maternal satisfaction despite a slightly faster onset with CSE and conversely less pruritus with low-dose epidurals. There was no difference in ability to mobilise, maternal hypotension, rate of caesarean birth or neonatal outcome. However, the significantly higher incidence of urinary retention, rescue interventions and instrumental deliveries with traditional techniques would favour the use of low-dose epidurals. It is not possible to draw any meaningful conclusions regarding rare complications such as nerve injury and meningitis.

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Background: 

Traditional epidural techniques have been associated with prolonged labour, use of oxytocin augmentation and increased incidence of instrumental vaginal delivery. The combined spinal-epidural (CSE) technique has been introduced in an attempt to reduce these adverse effects. CSE is believed to improve maternal mobility during labour and provide more rapid onset of analgesia than epidural analgesia, which could contribute to increased maternal satisfaction.

Objectives: 

To assess the relative effects of CSE versus epidural analgesia during labour.

Search strategy: 

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (28 September 2011) and reference lists of retrieved studies. We updated the search on 30 June 2012 and added the results to the awaiting classification section.

Selection criteria: 

All published randomised controlled trials (RCTs) involving a comparison of CSE with epidural analgesia initiated for women in the first stage of labour. Cluster-randomised trials were considered for inclusion. Quasi RCTs and cross-over trials were not considered for inclusion in this review.

Data collection and analysis: 

Three review authors independently assessed the trials identified from the searches for inclusion, assessed trial quality and extracted the data. Data were checked for accuracy.

Main results: 

Twenty-seven trials involving 3274 women met our inclusion criteria. Twenty-six outcomes in two sets of comparisons involving CSE versus traditional epidurals and CSE versus low-dose epidural techniques were analysed.

Of the CSE versus traditional epidural analyses five outcomes showed a significant difference. CSE was more favourable in relation to speed of onset of analgesia from time of injection (mean difference (MD) -2.87 minutes; 95% confidence interval (CI) -5.07 to -0.67; two trials, 129 women); the need for rescue analgesia (risk ratio (RR) 0.31; 95% CI 0.14 to 0.70; one trial, 42 women); urinary retention (RR 0.86; 95% CI 0.79 to 0.95; one trial, 704 women); and rate of instrumental delivery (RR 0.81; 95% CI 0.67 to 0.97; six trials, 1015 women). Traditional epidural was more favourable in relation to umbilical venous pH (MD -0.03; 95% CI -0.06 to -0.00; one trial, 55 women). There were no data on maternal satisfaction, blood patch for post dural puncture headache, respiratory depression, umbilical cord pH, rare neurological complications, analgesia for caesarean section after analgesic intervention or any economic/use of resources outcomes for this comparison. No differences between CSE and traditional epidural were identified for mobilisation in labour, the need for labour augmentation, the rate of caesarean birth, incidence of post dural puncture headache, maternal hypotension, neonatal Apgar scores or umbilical arterial pH.

For CSE versus low-dose epidurals, three outcomes were statistically significant. Two of these reflected a faster onset of effective analgesia from time of injection with CSE and the third was of more pruritus with CSE compared to low-dose epidural (average RR 1.80; 95% CI 1.22 to 2.65; 11 trials, 959 women; random-effects, T² = 0.26, I² = 84%). There was no significant difference in maternal satisfaction (average RR 1.01; 95% CI 0.98 to 1.05; seven trials, 520 women; random-effects, T² = 0.00, I² = 45%). There were no data on respiratory depression, maternal sedation or the need for labour augmentation. No differences between CSE and low-dose epidural were identified for need for rescue analgesia, mobilisation in labour, incidence of post dural puncture headache, known dural tap, blood patch for post dural headache, urinary retention, nausea/vomiting, hypotension, headache, the need for labour augmentation, mode of delivery, umbilical pH, Apgar score or admissions to the neonatal unit.

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