The extension of labour epidural analgesia for Caesarean section

Abstract

Despite the increasing popularity of epidural analgesia in obstetrics, most Caesarean sections in the United Kingdom are still performed under general anaesthesia.' Where epidural analgesia has been established to provide pain relief in labour, extension of the block for Caesarean section is usually possible and can avoid the necessity for general anaesthesia. This paper reports the outcome of applying this policy in 722 consecutive cases. MethodThe implications of epidural analgesia for Caesarean section were explained to the patients and the block extended by a dose of 16 ml bupivacaine (Marcain) 0.5 %, without adrenaline, 8 ml with the patient in the left lateral position, and, after an interval of 5 min, the remainder in the right lateral position. When necessary, additional bupivacaine was given to ensure that analgesia extended to all nerve roots below the sixth thoracic dermatome. All patients received a fluid load (approximately I litre) of either dextrose 5 % in water or Hartmann's solution during extension of the block. The arterial blood pressure was recorded at intervals of I-min using an 'Arteriosonde' automatic blood pressure recorder. Hypotension, defined as a fall in systolic blood pressure below 90 mmHg or a reduction of more than 30% of the initial systolic value, was corrected by increasing the rate of intravenous infusion and, when considered necessary, by the intravenous administration of 10-15 mg ephedrine hydrochloride. A Crawford wedge was placed under the patient's right side and oxygen administered byaHudsonmaskwithaflowrateof 4litreslmin. AII patients remained unsedated until after delivery apart from any analgesic which may have been administered during labour before establishment of the epidural. Syntocinon 2 units was injected intravenously, followed by an infusion of 10 units syntocinon in 500 ml 5 : ; dextrose in water. When delivery was complete and the mother had seen her baby, most patients received intravenous papaveretum and hyoscine to a maximum dose of 20 and 0.4 mg respectively. The mothers were interviewed 2 to 3 days after operation and were encouraged to give a frank opinion of their experience. ResultsIn 168 patients (23.2%) no attempt was made to use the epidural for surgery and a general anaesthetic was administered for reasons summarised in Table 1. In the remaining 554 patients (76.8 %) it appcared that successful extension of the block had been achieved. In 533 of these patients (96.27;) the operation was completed under epidural analgesia alone; the

Conversion d’une analgésie péridurale pour travail obstétrical en une anesthésie péridurale pour césarienne

“…[18][19][20] At that time, this novel management strategy was particularly important considering that maternal mortality directly related to anesthesia was reported to be 36/100,000 CD. The vast majority were related to the complications of GA. 2 In a follow-up review in 1979, Milne et al 15 described the anesthetic management of 722 consecutive cases of an intrapartum CD and reported an overall 69% (533/772) success rate of conversion of ELA to ESA. At that time, unfortunately, 23.2% (168/772) of the women with ELA underwent GA with no attempt to utilize the in situ epidural catheter.…”

“…Over the three decades following the initial report by Milne et al, 17 several studies [6][7][8][9][10][11][12][13][14][15] described retrospective reviews of the anesthesia for intrapartum CD in parturients receiving ELA. Unfortunately, when the attempted conversion resulted in inadequate ESA, none of these studies focused on the anesthetic management in an attempt to identify interventions to potentially reduce the need for GA.…”

“…[2][3][4][5] One of the important advantages of epidural labour analgesia (ELA) is the potential for this analgesic modality to be rapidly converted to epidural surgical anesthesia (ESA). This capacity can facilitate CD thereby avoiding the inherent risks of GA. Several small studies [6][7][8][9][10][11][12] and three larger studies [13][14][15] have suggested a high conversion success rate (89-95%) of ELA to ESA for intrapartum CD. Unfortunately, the identification of significant risk factors for failed conversion of ELA to effective ESA, and the development of management strategies to improve conversion rates have not previously been elucidated.…”

Extension of epidural blockade for emergency Caesarean section

“…If adverse effects on the fetus are to be minimised, the analgesic block in labour must be converted rapidly to one adequate for Caesarean section. Milne and colleagues considered that fetal distress was a contraindication to extending pre-existing block [9], but it has been demonstrated that general anaesthesia places the mother at increased risk [5] without always decreasing the time to delivery [ 101. The establishment of epidural analgesia has been recommended in those at risk of requiring Caesarean section since it decreases time to surgery [lo].…”

“…Surgery was significantly delayed in those patients (group 2) who required an additional top-up (Table 1). This further delay Thoracic dermatornal level R L R L Pre top-up 9 8 9 9…”