AIIMS Delhi NO- 2019: An antenatal mother is admitted with complaints of eclampsia. What will be the loading dose of MgSO4 given to…

AIIMS Delhi NO- 2019

Obstetrics & Gynaecology

Medium

Appeared in: AIIMS Delhi NO- 2019

Explanation

The standard intravenous (IV) loading dose of MgSO4 for eclampsia is 4 grams, as recommended by established protocols like the Pritchard and Zuspan regimens.
Magnesium sulfate is typically available as a 50% solution, where 1 gram is contained in 2 mL of the solution.
Therefore, a 4-gram dose requires 8 mL of the 50% solution (4 g x 2 mL/g).
This 8 mL is then diluted with 12 mL of Normal Saline (NS) to create a total volume of 20 mL, which results in a 20% solution for safe IV administration.
The prepared 20 mL solution is administered slowly via IV push over a period of 5 to 10 minutes to prevent adverse effects.

Option A: This option describes preparing a 2-gram dose (4 mL of 50% MgSO4). This is half the standard loading dose and would be sub-therapeutic for controlling active eclamptic seizures.
Option C: This option describes preparing a 3-gram dose (6 mL of 50% MgSO4). This is below the recommended initial loading dose of 4 to 6 grams and may not be sufficient to achieve therapeutic anticonvulsant levels quickly.
Option D: This option describes preparing a 1-gram dose (2 mL of 50% MgSO4). This dose is far too low to be an effective loading dose for eclampsia and would have no significant anticonvulsant effect.

Clinical Relevance

Nursing practice connection: Use the key finding related to Calculation and administration of the intravenous loading dose of magnesium sulfate (MgSO4) for eclampsia to guide bedside assessment, documentation, and the next nursing action.
Accurate preparation and administration of the MgSO4 loading dose is a critical nursing responsibility in obstetric emergencies to prevent or control life-threatening eclamptic seizures.
Nurses must vigilantly monitor for signs of magnesium toxicity, which include loss of deep tendon reflexes (patellar reflex), respiratory depression (rate less than 12/min), and oliguria (urine output less than 30 mL/hr).
The antidote for magnesium toxicity, calcium gluconate (1g IV), must be immediately available at the patient's bedside whenever MgSO4 is being infused.

How to Approach the Question

First, identify the core question: It asks for the loading dose of MgSO4 for eclampsia.
Recall the standard treatment protocol for eclampsia. The standard IV loading dose is 4 grams.
Convert the gram dose to milliliters. Remember the common concentration is a 50% solution, which means 1 gram = 2 mL.
Calculate the volume needed: 4 grams × 2 mL/gram = 8 mL.
Recall the standard dilution required for safe IV administration. The 8 mL of MgSO4 is diluted with 12 mL of a compatible diluent like Normal Saline (NS).
Match this calculation (8 mL in 12 mL of NS) to the given options to identify the correct answer.

Concept Tested & Keywords

Concept Tested: Calculation and administration of the intravenous loading dose of magnesium sulfate (MgSO4) for eclampsia.
Stem keywords: eclampsia, antepartum mother, loading dose, MgSO4
Lead-in keywords: What will be
Negative lead-in flag: false

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E6 Midwifery Obstetrics and Gynecology Nursing Sandeep Kaur p. 36-44

E6 Obstetrics Williams p. 30-51