The use of epidural analgesia for delivery of twins has been controversial in the past. Early studies examining its influence on the progress of labour in singleton pregnancies suggested a prolonged second stage and an increase in mid-cavity forceps deliveries. This led to a reluctance to employ it in twin pregnancies (1). Studies specifically addressing the effect of epidural analgesia on the progress of labour in multiple pregnancies have not supported this. Dysfunctional and prolonged labour is well described in twin pregnancies, however, these do not appear to occur more commonly in the presence of epidural analgesia. The duration of first stage does not appear prolonged and the second stage may be shortened (1, 2, 3).
The incidence of instrumental deliveries is clearly increased in twin pregnancies, in association with prematurity and malpresentation (4). Epidural analgesia does not appear to increase the incidence of this (1). No studies to date have specifically addressed the merit of low concentrations of local anaesthetic agents in multiple pregnancy. Experience with singleton pregnancies on the progress of labour support a reduction in motor block and instrumental delivery with concentrations of bupivacaine of 0.125% or less (5, 6, 7). Progressive sparing of involuntary expulsive reflexes may be less desirable in the delivery of twins, especially for premature and breech infants (Figure 14.1). This implies a reduced role for very low concentration solutions.
Continuous epidural analgesia would appear to achieve many of the goals outlined for twin deliveries. It provides satisfactory analgesia throughout first and second stages, and is readily modified to provide conditions for either caesarean section or instrumental vaginal delivery. As with other regional techniques, it does not provide uterine relaxation. Traditionally this necessitated general anaesthesia. More recently, parenteral; or inhaled glyceryl trinitrate has been shown to achieve comparable uterine relaxation and is associated with a low side effect profile by virtue of its short duration of action (8) (Chapter 24). Other techniques available include epidural and subarachnoid opioids, continuous or intermittent subarachnoid blockade, caudal, and pudendal blockade (Chapter 70). Opioid analgesia provides acceptable analgesia for first stage, however is often inadequate for second stage. It does not achieve the perineal anaesthesia required for instrumental deliveries (9). Furthermore, the considerations of prematurity and potential for hypoxaemia lend support to the avoidance of depressant drugs in these infants. Subarachnoid blockade is limited by the need to repeat the block if instrumental delivery is imminent, and continuous infusions via a subarachnoid catheter are associated with a higher incidence of central nervous system infection and nerve injury (10). Trauma to the fetus as a result of passage of the needle through the sacral foramina is a described complication of caudal anaesthesia (Figure 22.1). Pudendal anaesthesia does not provide first stage analgesia and a failure rate of 50% has been reported with its use (11). Whether regional analgesia is employed or not, the requirements for general anaesthesia in the labour ward should be met in anticipation of this being required. Communication between staff is important to ensure that the potential dangers of anaesthetising for this procedure in this venue are well understood. Large bore venous access should be established and blood bank facilities readily available. Staff and facilities for resuscitation of the neonates should be prepared.
References:
1. Weekes ARL, Cheridjian VE, Mwanje DK 1977 Lumbar epidural analgesia in labour in twin pregnancy. Br. Med. J.; ii: 730.
2. Jaschevatzky OE, Shalit A, Levy Y, Grunstein S Epidural analgesia during labour in twin pregnancy . British Journal of Obstetrics and Gynecology. May 1977; 84, 327-331.
3. Schnider SM, Levinson G: Anesthesia for Obstetrics 3rd ed Williams and Wilkins, Sydney 1993. p302.
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5. Sanchez Pereles MC, Uribarn FJ, Gragera I. 0.065% Bupivacaine compared with 0.125% Bupivacaine continuously perfused epidurally during vaginal delivery. Rev. Esp. Anesthesiol. Banim. 93 40: 1 9-11
6. Stoddart AP, Nicholson KE, Popham PA. Low dose bupivacaine fentanyl infusions in labor and the mode of delivery. Anaesth. 1994 49:12 1087-1090
7. Bleyaert A, Soetens M, Vaes L, Van Steenberge AL, Van der Donck A: Bupivacaine, 0.125%, in obstetric epidural analgesia: experience in three thousand cases . Anesthesiology 1979, 51:435-8
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11. Scudamore JH, Yates MJ: Pudendal block - a misnomer? Lancet 1966; 1: 23