Primary outcome

To examine the risk factors for failed epidural blood patch (EBP) following post-dural puncture headache, in the obstetric population. Failure would be defined as lack of reduction in pain intensity by at least 50% at 24 h after application of EBP, compared to worst pain before EBP or a visual analogue pain score (VAS pain) of > 3 at 24 h.
Secondary outcomes

  1. European practices in the management of PDPH
  2. Incidence of significant PDPH and treatment failure in different countries in Europe
  3. Timing of the procedure (after diagnosis of PDPH) and the volume of blood injected in relation to success or failure Complications and side effects of EBP: Chronic headache and backache, neurological injuries, audiological or visual other chronic impairments
  4. Variation in practices for management of ADP in different countries would be assessed

Sample Size and Centres

Sample size calculation was based on the results of a previous study on success rate (including both partial or complete success) for the first EBP, which was found to be 73% when 15 – 20 ml EBP was used and 61% when 10 – 15 ml was used (Paech et al 2011). With these expected success rates, a Fisher’s exact test with a 0.050 two-sided significance level will have 80% power to detect the difference between these groups when the sample size in each group is 256. This gives a total of 512 patients who have an EBP injected. However, an estimated 50% patients with a PDPH have an EBP today. Therefore, we need to recruit approximately 1024 patients with PDPH in order that approx. 512 patients would receive an EBP.