Ultrasonographic Changes in Transorbital Measurement of Optic Nerve Sheath Diameter in Magnesium Sulfate-Treated Severely Preeclamptic Patients: A Prospective Observational Study.

Abstract

Introduction: Severe preeclampsia can lead to various complications including increased intracranial pressure (ICP) which can be catastrophic but difficult to detect because of variable nonspecific symptoms. Ultrasonography has been used as noninvasive measure to monitor optic nerve sheath diameter (ONSD) as a marker of raised ICP. Effect of MgSO₄ on ICP can modify the management approach, need for additional monitoring, targeting hemodynamic goals, timing of delivery, and choice of anesthesia. We evaluated the effect of MgSO₄ on raised ICP in severely preeclamptic patients using ultrasound-guided ONSD as a surrogate marker of ICP.

Methodology: This prospective observational study was conducted after ethical committee approval and written informed consent from patients. Ultrasound-guided ONSD was measured and compared in 47 severe preeclamptic patients before and at 1 h, 4 h, 12 h, and 24 h after starting MgSO₄ therapy. The analysis of data was done by one-way analysis of variance using Statistical Package for the Social Science.

Results: Mean ONSD was 5.56 ± 0.30 mm in our study group. ONSD above 5.8 mm was seen in 17 (36.17%) patients and was considered as marker of raised ICP. There was a significant decrease in ONSD after 4 h of administration of MgSO₄. No significant correlation was observed between mean arterial pressure, serum magnesium level, and ONSD.

Conclusion: Ultrasound-guided ONSD measurement can be used as a quick, noninvasive bedside tool in severe preeclamptic patient on MgSO₄ treatment as marker of ICP which help us in determining clinical severity, therapeutic response, and to decide further course of management.