LAUSR

The timely provision of reliable analgesia during labour remains a primary concern of anaesthetists covering delivery suite. Although approximately 20% of parturients (127,000 women) in England [1] (and up to 61% of mothers in the USA [2]) avail themselves of an epidural during labour, providing successful epidural analgesia is an imperfect art. The failure rate of neuraxial labour analgesia has been reported to be in the region of 8–23% [3], and many of these are primary failures, i.e. due to incorrect placement of the epidural catheter [4]. Whilst lumbar epidurals per se tend to have a higher success rate than thoracic [5], labour analgesia is often provided at short notice by junior anaesthetists, out-of-hours, to patients rendered relatively noncompliant through pain. Changes in maternal anatomy also contribute to failures: ultrasound assessment to compare women during pregnancy and 9 months post-delivery demonstrated that the soft tissue channel between spinal processes is smaller, the skin-epidural space distance is greater and the epidural space is narrower [6]. At best, failed labour analgesia leads to inadequate or delayed analgesia, reduced satisfaction and increased anaesthetic workload. At worst, in patients having epidurals sited because of significant cardiorespiratory disease or other comorbidities, failed analgesia could have significant impact on maternal and fetal outcomes. Therefore, any technique that aims to reduce the incidence of primary failure of labour analgesia is welcome. This issue of Anaesthesia contains an article by Al-Aamri et al. that examines the use of epidural pressure waveforms to achieve this [7]. But how does this technique fit into the gamut at our disposal to prevent primary analgesic failure?