Unexpectedly extensive conduction blocks in obstetric epidural analgesia

Life-threatening extensions of conduction block during obstetric epidural analgesia can be classified according to the risk to the mother. High blocks that occur in the presence of the anaesthetist should present a readily treatable problem. Reports of total spinal anaesthesia that occur with no anaesthetist in attendance call for a reappraisal of present practice. Changes in current anaesthetic practice, which might increase safety with epidural analgesia, are top-ups by midwives, but only when the anaesthetist is on the delivery suite; repeated assessment of the nature of the conduction block by an anaesthetist; and continuous infusions with anaesthetist-only top-ups.     

Some maternal complications of epidural analgesia for labour

A review of the maternal complications encountered in a consecutive series of over 27 000 lumbar epidural blocks (exclusive of epidurals administered for elective Caesarean section and complications of a relatively minor or fleeting nature) in a single obstetric unit is presented. There were nine potentially life threatening complications, of which only three caused real concern for the mother's safety. Six of these occurred with the first top-up, as given by the anaesthetist. The others were the result of three out of the approximately 100 000 top-ups administered by midwives. There were two serious, but not life-threatening complications, each of which led to the requirement of a laminectomy. In addition, there were 13 moderately serious and 17 mildly disturbing complications. All the mothers concerned made a full recovery. There was a large number of inconsequential or pseudocomplications which, although initially blamed upon the epidural, were later demonstrated to have been of a different origin. Consideration of this experience leads to the conclusion that if the rules of management are rigorously followed, epidural analgesia for labour and delivery, including topping-up by well-informed midwives, is characterised by an extremely high level of safety for the mother.     

Regional analgesia in early active labour: combined spinal epidural vs. epidural

We randomly allocated 93 women in early active labour and requesting epidural analgesia to receive either epidural ( n  = 48) or combined spinal–epidural analgesia ( n  = 45). For epidural analgesia 15 ml of bupivacaine 0.1% with 75 μg of fentanyl were injected into the epidural space. For combined spinal–epidural analgesia 1 ml of bupivacaine 0.25% with 25 μg of fentanyl were injected into the subarachnoid space. For both groups subsequent top-ups of 10 ml of bupivacaine 0.1% with fentanyl 20 μg were given using a lightweight patient-controlled epidural analgesia (PCEA) pump with a lockout time of 30 min. We assessed analgesia and the degree of motor blockade and found no significant differences in pain or maternal satisfaction scores between the two groups. The time to first top-up was significantly longer in the epidural group than in the CSE group (p = 0.01). The combined spinal–epidural group had significantly greater motor blockade at 30 min than the epidural group (p = 0.01), but there was no difference after this. The PCEA machine failed completely twice and temporarily many times. We conclude that the combined spinal–epidural technique confers no advantages in early active labour. Also, a lightweight PCEA pump needs to be more reliable before we can recommend its use.     

Reporting of 'hypotension' after epidural analgesia during labourEffect of choice of arm and timing of baseline readings

We studied 20 women in labour to see how reporting 'hypotension' after obstetric epidural analgesia is affected by position of the blood pressure cuff and baseline definition. Blood pressure was recorded from both arms simultaneously while the woman was semirecumbent and then in the left lateral position. Three readings were then taken after epidural bupivacaine, one left lateral and the remainder right lateral. Before the epidural, blood pressure in the dependent arm in the lateral position was similar to blood pressure in either arm in the semirecumbent position and an average of 10 mmHg (systolic) and 14 mmHg (diastolic) higher than blood pressure in the uppermost arm (p ≤ 0.00005). This difference persisted in both lateral positions as epidural analgesia became established. Choosing different definitions of hypotension, baselines and arm to measure blood pressure resulted in 'hypotension rates' between 0% and 75%. For blood pressure measurement in the lateral position, the blood pressure cuff should be placed on the dependent arm.     

A survey of epidural analgesia for labour in the United Kingdom

A postal survey of obstetric units throughout the UK was conducted to obtain information about the provision of epidural analgesia for labour. Ninety per cent of units offered a 24-h epidural service and the average epidural rate was 24%. The most commonly administered epidural test dose was 3 ml of bupivacaine 0.5% and bupivacaine 0. 25% was most often used as the initial epidural top-up. Continuous infusions of low-dose bupivacaine and opioid mixtures were the most popular method of maintenance epidural analgesia. Twenty-four per cent of units offered combined spinal-epidural analgesia in addition to standard epidural analgesia. Midwives played a prominent role in the administration of epidural bolus top-ups and also in the assessment and maintenance of continuous epidural infusions.     

Continuous versus intermittent epidural analgesia

A randomised study of 381 women was carried out to compare the obstetric outcome after epidural analgesia maintained by an intermittent top-up regimen or with a continuous infusion. The two groups were well matched with respect to age, parity, mode of onset of labour and indication for epidural. Maintenance of epidural analgesia by continuous infusion resulted in a significantly decreased need for top-up doses. A reduction in the incidence of hypotension, cardiotocographic evidence of intrapartum fetal hypoxia and Caesarean section was associated with this. It is concluded that the maintenance of epidural analgesia by continuous infusion is a safe and reliable method and may be more advantageous and less labour intensive than the traditional intermittent regimen.     

Dorsal column function after epidural and spinal blockade: implications for the safety of walking following low-dose regional analgesia for labour

Walking after regional blockade for labour using low-dose combinations of bupivacaine and fentanyl is possible due to the maintenance of lower limb motor power. In order to investigate concerns that dorsal column function, important in maintaining balance, is impaired after such techniques, clinical assessment of lower limb proprioception and vibration sense was evaluated in parturients after either low-dose epidural ( n  = 30) or spinal blockade ( n  = 30) for labour analgesia and compared with spinal anaesthesia ( n  = 30) for elective Caesarean section using a larger total dose of local anaesthetic. Of the patients receiving low-dose regional labour analgesia 7% ( n  = 4) had abnormal dorsal column function compared with 97% ( n  = 29) receiving spinal anaesthesia for Caesarean section (p < 0.001). All patients in the Caesarean section group developed lower limb motor weakness, compared with only 10% ( n  = 6) in the low-dose groups (p < 0.001). There were no significant differences between the low-dose groups with respect to sensory block, motor block or dorsal column function. Overall, 90% of patients receiving low-dose bupivacaine/fentanyl regional labour analgesia had both normal lower limb motor power and dorsal column function. Assessment of these parameters is recommended before allowing patients to walk after low-dose regional techniques for labour.     

Crystalloid versus colloid for circulatory preload for epidural Caesarean section

Sixty mothers were randomly allocated to receive either 2 litres of crystalloid or 1 litre of colloid solution (hydroxyethyl starch) in order to preload the circulation prior to elective Caesarean section under epidural anaesthesia. There were no differences in the incidence of hypotension, degree of haemodilution, umbilical cord blood gas tensions or umbilical blood osmolalities between the two groups.     

A change in resistance? A survey of epidural practice amongst obstetric anaesthetists

Five hundred members of the Obstetric Anaesthetists Association were surveyed regarding their technique for identification of the epidural space. Eighty-one per cent of the questionnaires were returned completed. Fifty-nine per cent of respondents first learned a loss of resistance to air technique, 33.4% to saline and 7.4% another technique. Presently, 37.1% and 52.7% use only a loss of resistance to air or saline, respectively. Six per cent use both techniques and 3.2% use other techniques. Twenty-eight per cent taught a loss of resistance to air, 57.2% taught a loss of resistance to saline and 12.9% taught both techniques. Twenty-three per cent changed from a loss of resistance to air, to a saline technique, and 4.2% vice versa. Forty-seven per cent of those using air felt that loss of resistance to air was not associated with a clinically significant difference in the incidence of accidental dural puncture compared with saline.     

Alteration of maternal posture and its immediate effect on epidural pressure

A study was undertaken to investigate the changes in pressure inside the epidural space in parturients in the first stage of labour. The purpose was to see whether acute local pressure changes in the epidural space were consistent with the hypothesis that there is physical movement of cerebrospinal fluid with certain changes in maternal posture. Pressure changes were measured via the epidural catheter through which continuous infusion epidural analgesia was administered, using a pressure transducer kept at the level of the lumbar spine. The mothers moved through a series of postures that reflected those expected during the course of labour and delivery. The pressure within the catheter was recorded during these manoeuvres. The pressure changes which were found, taken in conjunction with the associated investigations of others, are consistent with the hypothesis.     

Uterine rupture and epidural analgesia during trial of labour

A case of complete uterine rupture during a trial of labour in which epidural analgesia was used is described. The pain of uterine rupture was not masked by the addition of fentanyl 25 μg to bupivacaine 0.25% 6 ml but was relieved by bupivacaine 0.375% 6 ml.     

间断硬膜外间隙给药在分娩镇痛中的应用

背景 近年来,间断硬膜外间隙给药(intermittent epidural bolus,IEB)作为分娩镇痛的一种新型给药方式逐渐受到临床的关注. 目的 阐述当前IEB进行分娩镇痛的进展. 内容 综述IEB的局部麻醉药消耗量、镇痛效果、运动阻滞发生情况和对分娩结局的影响. 趋向 随着认识的深入,IEB将在分娩镇痛中得到更广泛的应用.     

Speed of injection and spread of bupivacaine in the epidural space

Speed of injection of bupivacaine was assessed in 73 women who received epidural analgesia in labour. Rapid injection was shown to produce quicker onset of epidural block and more reliable perineal anaesthesia than slow injection, but there was no difference in the final extent of the block.