Prolonged intrathecal catheterisation after inadvertent dural taps in labour

We were interested to read Dr Sprigge's account (Anaesthesia 1999; 54: 95–6) of two dural punctures in an obstetric patient who had previously suffered a dural tap in her first labour. In the light of this history, the anaesthetist must have been mindful of the possibility of a repeat occurrence as the Tuohy needle was advanced. We suggest that threading the catheter intrathecally when CSF was encountered might have averted the need to approach another interspace for labour analgesia, as well as the subsequent dural puncture while attempting a blood patch. In three cases of accidental dural puncture with 16-g Tuohy needles in the first stage of labour, 20-g epidural catheters were immediately inserted intrathecally. After delivery, the catheters were left in situ for 13–19 h [1]. Not only was analgesia (and, in one case, surgical anaesthesia) facilitated, but none of the patients developed a postdural puncture headache (PDPH). An incidence of 86% has been reported following conservative management of dural puncture with 16-g Tuohy needles [2]. The presence of an intrathecal catheter ‘plugs’ the dural tear, and facilitates development of an inflammatory reaction, with fibrin deposition around the catheter [3]. Since publication of this report, we have managed one accidental dural tap in labour in this way. The subarachnoid space was breached with a 16-g Tuohy needle in an 18-year-old primigravida in early labour. The 18-g epidural catheter was threaded 3 cm intrathecally. Good analgesia was provided by intermittent 2-ml top-ups of bupivacaine 0.25%, and the woman had a spontaneous vaginal delivery 18 h later. The catheter was left in situ for a further 10 h, and no headache ensued. In addition to the provision of analgesia/anaesthesia, intrathecal catheterisation eliminates the risk of high or total spinal block associated with epidural administration of local anaesthetic after prior dural tap [4]. In a survey of the management of dural taps in labour, only 1% of units routinely catheterised the subarachnoid space [5]. This practice requires obstetric anaesthetists to override the basic instinct to remove a Tuohy needle through which CSF appears. We suggest that if Dr Sprigge's patient returns in labour for a third time, the contingency plan in the event of another dural tap might be to thread the catheter intrathecally, and leave it for 12 h after delivery.