Effect of Magnesium Sulphate on the Intracranial Pressure of Preeclamptic Patients
Condition: Preeclampsia Severe
MeSH terms: Pre-Eclampsia
Study type: Observational

Summary: 
      It had been shown that high percentage of severe preeclampsia patients got a high cerebral
      perfusion pressure (CPP) due to abnormal autoregulation of cerebral blood vessels with
      associated endothelial dysfunction and disrupted blood brain barrier. Moreover, patients with
      high CPP is more likely to present with headache compared to other patients with normal
      CPP.In this particular scenario, use of magnesium sulphate is associated with marked
      reduction of CPP and. hence prevention of cerebral damage.This hypothesis was confirmed by
      new magnetic resonance techniques that demonstrated brain edema in eclampsia/ severe
      preeclampsia patient mostly due to vasogenic edema and less commonly attributed to cytotoxic
      edema.

      Changes in the optic nerve sheath diameter (ONSD) mirrors the changes in the Intracranial
      pressure(ICP), subsequently when the intracranial pressure increases the optic nerve sheath
      diameter (ONDS) also increases.

      The aim of this study is to determine the effect Magnesium sulphate infusion on intracranial
      pressure, in patients presented with severe preeclampsia by measuring changes in the ONSD
      using ultrasound examination.
    

Detailed description: 
      30 obstetric patients admitted to the HDU in Corniche Hospital for treatment of severe
      preeclampsia. Patients with the following criteria will be excluded from the current work:
      Patients undergone cranial or eye surgeries, Patients with known intracranial pathology,
      Patients suffering from glaucoma or any other eye pathology that prevent clear identification
      of the optic nerve, and Patients on drugs that may affect the cerebrospinal fluid [based on
      operator decision].

      In this prospective pilot study, patients who will fulfill the inclusion criteria will be
      recruited at the time of admission in HDU by the investigators. The ONDS will be measured
      before the commencement of Magnesium sulphate infusion, 1hr after finishing the loading dose,
      6 and 24 hrs after infusion started. Patients will be in supine position with the head of the
      bed less than 20 degrees. High frequency (7.5 MHz) linear probe will be used; it will be
      placed gently over both closed eye after liberal application of sterile gel, the patient will
      be instructed to look forward to align the optic nerve directly opposite to the probe. The
      ONSD will be measured 3mm behind the optic disc in both the sagittal and transverse planes
      and an average will be calculated and recorded. In the absence of complete visualization of
      the optic disc, the largest viewed diameter will be taken as the maximal ONSD. Hemodynamic
      variables & oxygen saturation will be recorded at the same times.
    

Intervention name(s): Optic nerve sheath diameter
Intervention type(s): Diagnostic Test
Intervention description(s): Optic nerve sheath diameter measurement using ultrasound
Observational model: Case-Only
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        obstetric patients admitted to the HDU at Corniche Hospital for treatment of severe
        preeclampsia