Learning Objectives and CME/Disclosure Information
This activity is intended for healthcare providers delivering care to women and their families.
After completing this activity, the participant should be better able to:
1. Restate the measures to prevent magnesium toxicity 2. Discuss measures to treat eclampsia
Estimated time to complete activity: 0.25 hours
Susan J. Gross, MD, FRCSC, FACOG, FACMG
President and CEO, The ObG Project
Disclosure of Conflicts of Interest
Postgraduate Institute for Medicine (PIM) requires faculty, planners, and others in control of educational content to disclose all their financial relationships with ineligible companies. All identified conflicts of interest (COI) are thoroughly vetted and mitigated according to PIM policy. PIM is committed to providing its learners with high quality accredited continuing education activities and related materials that promote improvements or quality in healthcare and not a specific proprietary business interest of an ineligible company.
The PIM planners and others have nothing to disclose. The OBG Project planners and others have nothing to disclose.
Faculty: Susan J. Gross, MD, receives consulting fees from Cradle Genomics, and has financial interest in The ObG Project, Inc.
Planners and Managers: The PIM planners and managers, Trace Hutchison, PharmD, Samantha Mattiucci, PharmD, CHCP, Judi Smelker-Mitchek, MBA, MSN, RN, and Jan Schultz, MSN, RN, CHCP have nothing to disclose.
Method of Participation and Request for Credit
Fees for participating and receiving CME credit for this activity are as posted on The ObG Project website. During the period from 12/31/2017 through 1/25/2023, participants must read the learning objectives and faculty disclosures and study the educational activity.
If you wish to receive acknowledgment for completing this activity, please complete the post-test and evaluation. Upon registering and successfully completing the post-test with a score of 100% and the activity evaluation, your certificate will be made available immediately.
For Pharmacists: Upon successfully completing the post-test with a score of 100% and the activity evaluation form, transcript information will be sent to the NABP CPE Monitor Service within 4 weeks.
Joint Accreditation Statement
In support of improving patient care, this activity has been planned and implemented by the Postgraduate Institute for Medicine and The ObG Project. Postgraduate Institute for Medicine is jointly accredited by the Accreditation Council for Continuing Medical Education (ACCME), the Accreditation Council for Pharmacy Education (ACPE), and the American Nurses Credentialing Center (ANCC), to provide continuing education for the healthcare team.
Physician Continuing Medical Education
Postgraduate Institute for Medicine designates this enduring material for a maximum of 0.25 AMA PRA Category 1 Credit(s)™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.
Continuing Nursing Education
The maximum number of hours awarded for this Continuing Nursing Education activity is 0.2 contact hours.
Designated for 0.1 contact hours of pharmacotherapy credit for Advance Practice Registered Nurses.
Eclampsia is a severe, life-threatening manifestation of preeclampsia. While long-term neurologic damage is rare, there is risk of maternal hypoxia and death. Most women will experience signs such as headaches or visual changes prior to a seizure.
Defined as convulsions during pregnancy and/or postpartum
Tonic-clonic, focal, or multifocal
Unexplained by other neurologic pathology
Consider other underlying cerebral conditions when
Seizures occur 2 to 3 days postpartum
Patient on magnesium sulfate
Note: Not all women will demonstrate classic features of preeclampsia (hypertension, proteinuria)
Magnesium Sulfate – Seizure Prophylaxis
Magnesium sulfate is the treatment of choice for seizure prophylaxis (ACOG recommended dosing)
Loading dose of 4–6 g of magnesium sulfate administered per infusion pump over 20–30 minutes (i.e., slowly) followed by a maintenance dose of 1-2 g per hour as a continuous intravenous infusion
Continue 24 hours postpartum
Additional dose of 2-4 g can be infused over 5 minutes
Sodium amobarbital: 250 mg IV in 3 minutes
Thiopental or phenytoin: 1,250 mg IV at a rate of 50 mg/minute
Patient should be managed in ICU
10 g initially as a loading dose (5 g IM in each buttock) followed by 5 g every 4 hours
Use if IV access limited
Mix with 1 mL xylocaine 2% to alleviate pain
Note: Magnesium sulfate should not be considered an antihypertensive agent
Magnesium Sulfate – When to Use
Severe features of preeclampsia
Administer to all women
No severe features of preeclampsia and systolic BP > 140 and < 160 mm Hg or diastolic BP > 90 and < 110 mm Hg
There is no consensus on this matter as prophylaxis will reduce eclampsia but 1 in 100 to 129 women need to be treated and side effects (although not life threatening) will increase
ACOG states that the decision to use magnesium sulfate when severe features are not present should be the decision of the “physician or institution, considering patient values or preferences, and the unique risk-benefit trade-off of each strategy”
Delivery and Postpartum
Continue infusion 24 hours postpartum
Begin infusion (if not yet running) before surgery and continue 24 hours postpartum
Discontinuing prior to operative vaginal birth or cesarean section to avoid uterine atony or anesthetic drug interactions is not recommended
Prevention of Magnesium Sulfate toxicity
Place Foley to monitor renal function (hourly output)
Confirm normal serum creatinine
Serial evaluation of patellar deep tendon reflexes
Monitor respiratory rate
Serum magnesium levels not routinely required
Monitor serum magnesium levels in setting of renal dysfunction and/or absence of patellar reflexes
Maintain serum concentrations 5 to 9 mg/dL (4–7 mEq/L) range
Predictive symptoms of magnesium sulfate toxicity
Loss of deep tendon reflexes >9 mg/dL (greater than 7 mEq/L)
Respiratory depression >12 mg/dL (greater than 10 mEq/L)
Cardiac arrest >30 mg/dL (greater than 25 mEq/L)
Notify appropriate health care provider
Discontinue magnesium infusion
Administer supplemental oxygen
Obtain a serum magnesium level
10 mL of 10% calcium gluconate IV (1 g total) and over 3 min (i.e., slowly) to avoid hypotension and/or bradycardia
Calcium effect (competitively inhibits magnesium at neuromuscular junction) can wear off if magnesium level stays high
Furosemide may help increase urinary excretion
Respiratory arrest: Intubation and assisted ventilation as indicated
Other Prophylactic Agents
Magnesium sulfate is superior to diazepam, phenytoin and lytic cocktail (chlorpromazine, promethazine, pethidine) in reducing significantly the risk of seizure recurrence
Cochrane Review 2010: Magnesium sulfate reduced eclampsia compared to phenytoin (relative risk 0.08, 95% CI 0.01 to 0.60)
Morbidity related to pneumonia, mechanical ventilation and admission to an intensive care unit are significantly reduced with the use of magnesium sulfate compared with phenytoin
Magnesium sulfate does not cause maternal or newborn CNS depression
Diazepam or lorazepam does stop or shorten seizures, but risk of maternal apnea and/or cardiac arrest
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Disclosure of Unlabeled Use
This educational activity may contain discussion of published and/or investigational uses of agents that are not indicated by the FDA. The planners of this activity do not recommend the use of any agent outside of the labeled indications.
The opinions expressed in the educational activity are those of the faculty and do not necessarily represent the views of the planners. Please refer to the official prescribing information for each product for discussion of approved indications, contraindications, and warnings.
Participants have an implied responsibility to use the newly acquired information to enhance patient outcomes and their own professional development. The information
presented in this activity is not meant to serve as a guideline for patient management. Any procedures, medications, or other courses of diagnosis or treatment discussed or suggested in this activity should not be used by clinicians without evaluation of their patient’s conditions and possible contraindications and/or dangers in use, review of any applicable manufacturer’s product information, and comparison with recommendations of other authorities.
Jointly provided by
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