A nurse is assessing a client with severe pre-eclampsia who is receiving magnesium sulfate infusion.

Which finding should alert the nurse to suspect magnesium toxicity?

This is a manifestation of severe preeclampsia that indicates liver involvement and can precede a seizure.

The nurse should report this finding to the provider immediately and prepare for possible delivery of the baby.

Choice A is wrong because blood pressure of 150/90 mm Hg is a sign of mild preeclampsia, not severe.Severe preeclampsia is diagnosed when the systolic pressure is 160 mm Hg or higher or the diastolic pressure is 110 mm Hg or higher.

Choice B is wrong because urine protein of 2+ is also a sign of mild preeclampsia, not severe.Severe preeclampsia is diagnosed when the urine protein is 3+ or higher.

Choice D is wrong because facial edema is a common finding in normal pregnancy and does not indicate severe preeclampsia.Other signs of severe preeclampsia include headache, blurred vision, oliguria, thrombocytopenia, and pulmonary edema.

The client has no seizures or eclampsia.This outcome would indicate that the magnesium sulfate therapy is successful because magnesium sulfate is a mineral that reduces seizure risks in women with preeclampsia.

Some additional information for the other choices are:

• Choice B. The client delivers a healthy baby vaginally.

This outcome is desirable but not directly related to the effectiveness of magnesium sulfate therapy.Magnesium sulfate can help prolong a pregnancy for up to two days to allow drugs that speed up the baby’s lung development to be administered, but it does not guarantee a vaginal delivery or a healthy baby.

• Choice C. The client has normal blood pressure and urine output.

This outcome is also desirable but not directly related to the effectiveness of magnesium sulfate therapy.

Magnesium sulfate may help reduce blood pressure in some cases, but it is not the primary treatment for hypertension in preeclampsia.Other medications such as antihypertensives are usually prescribed for that purpose.Urine output should be monitored closely while receiving magnesium sulfate therapy, as a decrease may indicate toxicity or kidney impairment.Urine output should be at least 30 mL/hour while administering magnesium sulfate.

• Choice D. The client has improved liver function and platelet count.

This outcome is also desirable but not directly related to the effectiveness of magnesium sulfate therapy.

Magnesium sulfate does not affect liver function or platelet count in preeclampsia.These parameters may improve after delivery of the placenta, which is the main cause of preeclampsia.

Normal ranges for blood pressure, urine output, liver function and platelet count are:

• Blood pressure: less than 140/90 mm Hg

• Urine output: at least 30 mL/hour

• Liver function: AST and ALT less than 40 U/L, LDH less than 600 U/L, bilirubin less than 1.2 mg/dL

• Platelet count: 150,000 to 450,000 per microliter of blood