Post dural puncture headache can be a debilitating complication of epidural and subarachnoid anaesthesia for a new mother. In a survey of 18,337 epidurals and 5021 subarachnoid blocks performed for obstetric procedures over a 23-year period in a district general hospital maternity unit, there were 167 recognised accidental dural punctures after epidurals (0.91%), with 147 patients (88%) developing post dural puncture headache. In addition, there were 52 post dural puncture headaches after subarachnoid blocks (1.04%). Successful management of accidental dural puncture and post dural puncture headache requires adherence to clear policies and protocols, with close follow-up of patients by an experienced obstetric anaesthetist.
◊ Reviewed by M. Vercauteren, MD, PhD
Professor, Dept. of Anesthesia, Antwerp University Hospital, Antwerp, Belgium
The authors should be congratulated to this survey. The incidence of ADT corresponds with the actually accepted figure for training hospitals i.e. <1%. In addition, the rather poor success of a first and especially a second EBP corresponds with our experience (1).
Although the covered period from 1983 to 2005 seems impressive, it also constitutes a major flaw of this survey because during these 23 years many practices have changed:
1.The needle design has changed from large Quincke needles (early 80’s) to small needles with a pencil-point design (early 90’s). The authors admit a significant improvement when they abandoned the Quincke needles as their incidence of ADT fell from 3.5% to 0.9% after 1992.
2. In the early 90’s, many UK hospitals performed the CSE technique for labour and caesarean section. Therefore, it is unclear whether headache might have been caused by an ADT or the intended spinal component. The authors either excluded these patients or never practiced this neuraxial technique.
3. The loss of the resistance to air technique was more popular some decades ago whereas actually most hospitals have changed to saline to detect the epidural space. It has been shown that the loss of resistance to air may cause more taps while accidental subarachnoidal injection of air may also cause headache though with different characteristics [2]. The authors left the choice of air or saline to the discretion of the anaesthetist but no attention was paid to the choice made.
4. In the early 80’s an EBP was only exceptionally offered in case of PDPH. In line with this, the incidence of EBPs doubled when comparing the first and last 5 years of the survey period. Especially with progressively shorter hospital stays, the pressure upon anaesthetists is increasing to accelerate the performance of an EBP enabling the mother to care for the newborn. However, performing EBP too early may decrease its success rate. In our survey of 200 blood patches, the majority of repeated patching was required after labour analgesia, as young mothers received their first EBP within less than 48 hours [1]. On the other hand, waiting 3 days for the first and 4-5 days for the second EBP, as in the present survey, may increase the risk of complaints and of litigation, as parturients (and medical insurances?) no longer accept such long supine bed rest and hospital stays.
5. The attitude following an ADT has also significantly changed. Whereas many years ago the epidural was placed at another interspace, nowadays most anaesthetists will introduce a catheter intrathecally through the Tuohy needle penetrating the dura. This may reduce the incidence of PDPH when this catheter is left in place for at least 24 hours. Although on the ‘dural tap survey form’ the anaesthetist was asked how the anaesthetic management proceeded, with a spinal catheter as a possible solution, no further details were communicated. It is theoretically possible that the 12% of patients not experiencing PDPH were treated with such a spinal catheter.
6. Still many anaesthetists, regardless of proven benefit, will not allow the parturient to actively press (bear down) during the second stage of labour. It is unclear whether this change of practice has influenced the incidence of PDPH despite registration of spontaneous or instrumental delivery.
All this demonstrates that reviews over extremely long periods do not allow to provide clear ‘take home’ messages. A split in shorter intervals might have added value and a more encouraging perspective.
[1] Vercauteren MP, Hoffmann VH, Mertens E, Sermeus L, Adriaensen HA.
Seven-year review of requests for epidural blood patches for headache after dural puncture: referral patterns and the effectiveness of blood patches. Eur J Anaesthesiol. 1999; 16: 298-303.
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[2] Evron S, Sessler D, Sadan O, Boaz M, Glezerman M, Ezri T.
Identification of the epidural space: loss of resistance with air, lidocaine, or the combination of air and lidocaine. Anesth Analg. 2004; 99: 245-50.
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