Optic Nerve Sheath Diameter in Pre-Eclamptic Parturient Receiving Magnesium Sulfate Combined With Dexmedetomidine

Using Optic Nerve Sheath Diameter to Monitor Intracranial Tension in Pre-Eclamptic Parturient Receiving Magnesium Sulfate in Combination With Dexmedetomidine

Dexmedetomidine was reported to effectively reduce cerebral metabolism and ICP by decreasing cerebrospinal fluid pressure in patients with cerebral tumors or head injuries that require craniotomy. However, it was also reported to exhibit no effect on ICP. the effect of MgSO4 associated with dexmedetomidine on ONSD in severely pre-eclamptic parturient has been understudied . Though this study aims to evaluate the effect of dexmedetomidine infusion on raised ICP in severely pre-eclamptic parturients using ocular ultrasonography to determine ONSD as a measure of ICP.

Study Overview

• Status: Completed
• Conditions: Optic Nerve Sheath Diameter; Preeclampsia Severe
• Intervention / Treatment: Drug: Dexmedetomidine; Drug: Saline

Detailed Description

Dexmedetomidine, a highly selective α-2-receptor agonist, is a first-line sedative medication in ICU and has been increasingly used for obstetric anesthesia. Dexmedetomidine, which provides light sedation, possesses analgesic, sympatholytic, anxiolytic properties and attenuates the stress response without significant respiratory depression. In addition, dexmedetomidine-induced stimulation of postsynaptic alpha-2 adrenergic receptor on the cerebral blood vessels can cause cerebral vasoconstriction and decrease cerebral blood flow. However, the effects of dexmedetomidine on ICP are controversial.

Clinical signs of raised ICP are not specific and often difficult to interpret, especially during pregnancy and pre-eclampsia. Though the use of invasive devices is considered a gold standard in the measurement of ICP, Ocular sonography is a promising bedside tool, which serves as a noninvasive, readily available, and cost-effective means for indirectly measuring ICP.

Bedside ultrasound can be used as a point-of-care tool for rapidly measuring the optic nerve sheath diameter (ONSD), which is a validated indirect means for measuring ICP. An increase in ICP reflects as a raised ONSD since the optic nerve is surrounded by Dural sheath and cerebrospinal fluid (CSF) containing subarachnoid space, which is distensible in the retrobulbar segment, particularly when CSF pressures rise.

• Study Type: Interventional
• Enrollment (Actual): 50
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Egypt
  • Qalubia
    • Banhā, Qalubia, Egypt, 13511
      • Samar Rafik Amin

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 40 years (Adult)
• Accepts Healthy Volunteers: No

Study Population

preeclampsia with severe features will be defined using the American College of Obstetricians and Gynecologist Task Force on Hypertension in Pregnancy recommendation [16]; as raised blood pressure (BP) >160/110 mmHg, proteinuria more than 5 g/day, oliguria (<500 mL/day), elevated serum creatinine, intrauterine growth retardation, pulmonary edema, central nervous system manifestations (headache, visual disturbances, seizures, and stroke), hepatic tenderness, or the HELLP syndrome.

Description

Inclusion Criteria:

• aged18 to 40 years with
• at least 36 weeks gestation
• admitted with diagnosis of severe pre-eclampsia and scheduled to receive Magnesium Sulphate therapy before delivery

Exclusion Criteria:

• Presence of ocular wound or Prior ocular surgery
• emergency cases, and evidence of fetal compromise
• HELLP syndrome (hemolysis, elevated liver enzymes, and low platelet levels)
• Chronic hypertension
• Hyperthyroidism, and diabetes mellitus
• Presence of pre-existing chronic lung and/or cardiac diseases
• Presence of pre-existing chronic renal and/or hepatic diseases
• Presence of any chronic diseases of central nervous system.
• known allergies to the tested drug.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Group (D); Patients will receive a loading dose of iv dexmedetomidine followed by a maintenance infusion.	Drug: Dexmedetomidine; pre-eclamptic Patients will receive a loading dose of iv dexmedetomidine (0.5 ug/kg) diluted in 50 ml saline and given over 10 min, followed by a maintenance infusion of (0.2 ug/kg/h) diluted in 200 ml saline till The sedation scores on the Richmond Agitation and Sedation Scale was -2 to +1 (lightly sedated to restless).
Placebo Comparator: Group (C); patients will receive saline loading and infusion	Drug: Saline; pre-eclamptic patients will receive 50 ml saline loading for 10 min followed by 200 ml saline infusion

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Optic nerve sheath diameter (ONSD) measurments following Drug administration	Baseline (before starting MgSO4 therapy) then at 1, 6, 12 and 24 hours postoperative

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The incidence of raised ICP in severe pre-eclampsia	ONSD >5.0 mm	Baseline (before starting MgSO4 therapy), and during 24 hours postoperative.
Sedation Score	the Richmond Agitation and Sedation Scale (RASS), on which scores range from -5 [unresponsive] to +4 [combative].	every 2 hours after drug infusion, till 24 postoperative hours
Heart Rate (HR)		Baseline (before starting MgSO4 therapy) then every 2 hours till 24 postoperative hours
mean arterial pressure (MAP) changes.		Baseline (before starting MgSO4 therapy) then every 2 hours till 24 postoperative hours
The duration of hospital stay	defined as time from the day of operation to the day of discharge	one month after delivery

Collaborators and Investigators

• Sponsor: Benha University

Study record dates

Study Major Dates

• Study Start (Actual): June 6, 2023
• Primary Completion (Actual): May 10, 2024
• Study Completion (Actual): June 15, 2024

Study Registration Dates

• First Submitted: November 1, 2022
• First Submitted That Met QC Criteria: November 8, 2022
• First Posted (Actual): November 9, 2022

Study Record Updates

• Last Update Posted (Actual): May 23, 2025
• Last Update Submitted That Met QC Criteria: May 20, 2025
• Last Verified: May 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Pregnancy Complications; Hypertension, Pregnancy-Induced; Pre-Eclampsia; Physiological Effects of Drugs; Molecular Mechanisms of Pharmacological Action; Peripheral Nervous System Agents; Central Nervous System Depressants; Sensory System Agents; Analgesics, Non-Narcotic; Analgesics; Neurotransmitter Agents; Hypnotics and Sedatives; Adrenergic alpha-2 Receptor Agonists; Adrenergic alpha-Agonists; Adrenergic Agonists; Adrenergic Agents; Dexmedetomidine
• Other Study ID Numbers: RC 23.9.2022

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No