Alteration in Hearing Following Accidental Dural Puncture. A Study in Parturients
Condition: Parturients in Labour
Study type: Observational

Summary: 
      Headache following accidental dural punction as during epidural analgesia can be severe and
      sometimes very disabling. The incidence of PDPH is 10-40%, most starting within 48 h of dural
      puncture. Although spontaneous resolution of headaches is common in most patients within 7
      days, in 20% can they be persistent and in some very disabling. The exact reason for the
      characteristic headache is unknown, but it is believed to be the result of leakage of
      cerebro-spinal fluid (CSF) from the dural puncture. The greater the leakage of CSF, the more
      severe and persistent the headache. This is why larger needles (lower gauge) are known to
      have a higher incidence of PDPH. However, the type of needle also seems to play an important
      role in the likelihood of PDPH.

      Headache following accidental PDPH is very typical as it increases significantly when sitting
      or standing and often disappears completely on lying down. It is typically located in the
      back of the head, accentuated by light and often decreases with intake of large quantity of
      fluids. In many cases, it is self-limiting and most often decreases with time and bed rest.

      Diagnosis of PDPH is clinical and sometimes difficult. It is well known that liquor leakage,
      as following spinal anaesthesia, results in partial loss of unilateral or bilateral hearing
      that can be detected by oto-acoustic hearing loss. We plan to use this knowledge and test the
      hypothesis that measurement of hearing loss may be a diagnostic method for confirmation of
      clinical symptoms and signs of accidental PDPH.
    

Detailed description: 
      Parturients who have received epidural analgesia during labour would be included in this
      study and these would comprise of:

        1. patients without clinical symptoms of postdural puncture headache

        2. patients with clinical symptoms of postdural puncture headache

      In addition, a control group of parturients who have not received an epidural analgesia would
      constitute the control group.

      All patients would have audiometry (oto-acoustic emission - OAE, and auditory steady state
      response - ASSR) done following diagnosis of PDPH. Subsequently, the patients would be
      observed for 24 h to assess whether the headache resolves spontaneously. A new audiometry
      would be done at this stage. Those patients with substantial evidence of PDPH at this stage
      would receive an epidural blood patch (EBP) and a new audiometric assessment would be made
      after 4 h and 24 h to assess whether any audiometric deficit has resolved or not. All
      patients would have a similar measurement of hearing after 3 months when it is believed that
      most patients have returned to normal hearing. In addition to audiometric analysis, patients
      would be asked to fill out a detailed PDPH questionnaire at the same time periods.

      All measurements would be compared with patients who have received an EDA but without PDPH
      and those who have not received an EDA.
    

Observational model: Case-Control
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Experimental group: Parturients in labour with epidural and having PDPH Control group -
        EDA: Parturients in labour with epidural and NOT having PDPH Control group - No EDA:
        Parturients in labour without epidural and NOT having PDPH
      
Keywords: Parturients; Analgesia, epidural; Headache, post-dural puncture