Martin Dresner

Anaesthesia for caesarean section in women with complex cardiac disease: 34 cases using the Braun Spinocath® spinal catheter

BACKGROUND Cardiac disease in pregnancy is now the leading medical cause of maternal mortality in the UK. Whilst anaesthesia has not been the precipitant of this morbidity, its safety cannot be taken for granted. Spinal catheter anaesthesia, a relatively uncommon choice in obstetric practice, offers the potential of maintaining haemodynamic stability through accurate and gradual titration of neuraxial blockade. METHODS Thirty-four women with cardiac disease requiring caesarean section were selected for spinal catheter anaesthesia. All received invasive arterial pressure measurement but in only two were central venous catheters sited. After inserting a 24-gauge Braun Spinocath, spinal anaesthesia was induced using diamorphine 300 microg and 0.5% hyperbaric bupivacaine in 0.25-mL increments. Technical problems, block quality and haemodynamic stability were recorded. RESULTS Successful anaesthesia was achieved in 33 women. Spinal catheterisation proved impossible in one case, but the catheter was successfully used to provide epidural anaesthesia. There were no conversions to general anaesthesia. Eight women (24%) received supplementation with intravenous alfentanil, but all reported high satisfaction. Mild, transient hypotension occurred in six women (18%), and there was one case of vasovagal syncope induced by rapid exteriorisation of the uterus. Three patients (8.8%) experienced post dural puncture headache requiring a blood patch; two had received repeat dural puncture during catheter insertion. CONCLUSIONS Incremental spinal catheter anaesthesia offers effective anaesthesia with excellent haemodynamic control. Post dural puncture headache is of concern, and whilst it may be addressed by product modification, it currently limits widespread use of the Braun Spinocath in obstetric practice.

Meningococcal meningitis after combined spinal-epidural analgesia

We present a case of bacterial meningitis in a 32-year-old parturient following combined spinal-epidural analgesia for labour. The patient made a full recovery with no residual neurological sequelae, but important lessons were learnt. Firstly, investigating obstetricians and physicians were unaware that a combined spinal-epidural technique included an intrathecal component, so did not consider treating organisms that might be acquired by this route. Anaesthetists, on the other hand, in the absence of an isolated organism, saw this as a likely combined spinal-epidural complication. Infectious disease experts eventually diagnosed community-acquired meningococcal meningitis by analysing bacterial deoxyribonucleic acid (DNA) fragments using polymerase chain reaction studies. This test and the management of suspected meningitis in the post-partum period are discussed.

The management of breakthrough pain during labour.

There is a long history of attempts to alleviate the pain of childbirth, particularly in Asian and Middle Eastern civilisations. In the UK, it was the administration of chloroform to Queen Victoria by John Snow in 1853 that is widely credited with popularizing the idea that labour pain should and could be treated. Medical analgesia is now well established around the globe with a wealth of research evidence describing methods, efficacy and complications.In this article, we define ‘primary breakthrough pain’ as the moment when a woman first requests analgesia during labour. The management of this can include simple emotional support, inhaled analgesics, parenteral opioids and epidural analgesia.‘Secondary breakthrough pain’ can be defined as the moment when previously used analgesia becomes ineffective. We concentrate our discussion of this phenomenon on the situation when epidural analgesia begins to fail. Only epidural analgesia offers the potential for complete analgesia, so when this effect is lost the recipient can experience significant distress and dissatisfaction. The best strategy to avert this problem is prevention by using the best techniques for epidural catheterisation and the most effective drug combinations. Even then, epidurals can lose their efficacy for a variety of reasons, and management is hampered by the fact that each rescue manoeuvre takes about 30 minutes to be effective. If the rescue protocol is too cautious, analgesia may not be successfully restored before delivery, leading to patient dissatisfaction. We therefore propose an aggressive response to epidural breakthrough pain using appropriate drug supplementation and, if necessary, the placement of a new epidural catheter. Combined spinal epidural techniques offer several advantages in this situation. The goal is to re-establish analgesia within 11 hour.The primary aim of pain management during labour and delivery is to provide the level of comfort determined as acceptable to each individual woman. Some require little or no analgesia, while others demand complete abolition of pain. Whatever the individual’s personal point of breakthrough pain is, supporting clinicians should respond logically and rapidly to re-establish analgesia using locally agreed protocols. This approach will maximize patient satisfaction and hopefully increase the pleasure and satisfaction of childbirth.

Morbidly obese patients should not be anaesthetised by trainees without supervision

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Ropivacaine and bupivacaine with fentanyl for labor epidural anesthesia.

Meister et al. (1) compared epidural analgesia with 0.125% ropivacaine/fentanyl versus 0.125% bupivacaine/fentanyl during obstetric labor. The local anesthetics used were of equal concentration but were not equianalgesic. Minimum local analgesic concentration studies have demonstrated that ropivacaine has only 0.6 the potency of bupivacaine (2,3), and therefore, equiconcentration but not equipotent drugs have been used. The concentrations used, 0.125% local anesthetic, are both above their calculated 95% effective doses, and therefore, both would be expected to provide effective analgesia, as demonstrated in the study. That significantly less motor block was seen in the ropivacaine/ fentanyl group is not surprising in view the lower potency of ropivacaine. The authors state that ropivacaine cannot be less potent than bupivacaine as less supplemental analgesia was needed in the ropivacaine group. This simply reflects the longer half-life of ropivacaine compared with bupivacaine, a result of its S-enantiomer form and its greater vasoconstrictor action. The conclusion that the drugs appear to be equipotent at clinically used concentrations only reflects the higher than 95% effective dose concentrations being used.