A nurse is assisting in the care of a client who is in active labour. The nurse notes variable decelerations of the FHR. The nurse should identify which of the following is a cause of variable decelerations.

The correct answer is choice A: Respiratory rate of 16/min.

Choice A rationale:

A respiratory rate of 16/min is within the normal range for adults, which is typically between 12 to 20 breaths per minute. In the context of severe preeclampsia, maintaining a normal respiratory rate is crucial when administering magnesium sulfate IV, as one of the signs of magnesium toxicity is respiratory depression. Therefore, a respiratory rate of 16/min indicates that the client is not experiencing respiratory depression and it is safe to continue the magnesium sulfate infusion.

Choice B rationale:

A heart rate of 60/min is at the lower end of the normal range, which is 60 to 100 beats per minute for adults. However, bradycardia or a low heart rate can be a sign of magnesium sulfate toxicity, especially if accompanied by other symptoms such as hypotension or altered mental status. Without additional context, a heart rate of 60/min alone does not necessarily indicate it is unsafe to continue the infusion, but it would require further assessment.

Choice C rationale:

A urine output of 50 mL in 4 hours is significantly below the expected minimum of 30 mL/hour for adults. Adequate urine output is an important indicator of kidney function and is essential for the excretion of magnesium. In the case of magnesium sulfate infusion for severe preeclampsia, a low urine output could indicate renal insufficiency and an increased risk of magnesium toxicity. Therefore, a urine output of 50 mL in 4 hours is a contraindication for continuing the infusion without further evaluation.

Choice D rationale:

Diminished deep-tendon reflexes can be a sign of magnesium toxicity. Deep-tendon reflexes are assessed to monitor for signs of magnesium overdose during infusion, as magnesium acts as a central nervous system depressant at high levels. If deep-tendon reflexes are diminished, it may suggest that the serum magnesium levels are too high, and the infusion should be paused or discontinued to prevent further toxicity.

In summary, the only finding that clearly indicates it is safe to continue the magnesium sulfate infusion is a normal respiratory rate, as provided in choice A. The other options either require further assessment or are indicators of potential magnesium toxicity.

Choice A rationale :

Vitamin K decreases the newborn's risk of jaundice. Rationale: This statement is incorrect. Vitamin K plays no direct role in reducing the risk of jaundice in newborns. Jaundice is primarily caused by the accumulation of bilirubin in the blood, which is a different issue than hemorrhagic disorders.

Choice B rationale

Vitamin K decreases the newborn's risk of healthcare-associated infections. Rationale: This statement is incorrect. Vitamin K is not related to reducing the risk of healthcare-associated infections. Its main function is related to blood clotting and preventing hemorrhagic disorders.

Choice C rationale

Vitamin K decreases the newborn's risk of hemorrhagic disorders. Rationale: This statement is correct. Vitamin K is essential for the production of clotting factors in the blood, which helps prevent bleeding or hemorrhagic disorders in newborns. Newborns are born with low levels of vitamin K, so administering a vitamin K injection at birth is a common practice to prevent potential bleeding issues.

Choice D rationale

Vitamin K decreases the newborn's risk of complications from the Hepatitis B vaccine. Rationale: This statement is incorrect. Vitamin K is not directly related to reducing the risk of complications from the Hepatitis B vaccine. The vaccine is designed to protect against Hepatitis B infection, and vitamin K is not involved in its efficacy or safety.