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.

Choice A rationale:

The nurse should monitor the urinary output of the client as it can be an important indicator of hydration and renal function. However, in this specific scenario, the administration of oxytocin via IV infusion after a vaginal delivery requires a different focus for evaluating medication effectiveness.

Choice B rationale:

The nurse should primarily assess the fundal consistency to evaluate the effectiveness of oxytocin. Oxytocin is often administered after childbirth to promote uterine contractions and prevent postpartum hemorrhage. Checking the fundal consistency helps determine if the uterus is contracting appropriately. A firm fundus indicates effective contractions, which are essential for controlling bleeding and preventing complications.

Choice C rationale:

Monitoring the pulse rate is a vital aspect of patient care, but it may not be the most relevant parameter to evaluate the effectiveness of oxytocin. Pulse rate can give information about the client's cardiovascular status and general well-being, but it does not directly assess the medication's impact on uterine contractions.

Choice D rationale:

Similarly, keeping an eye on blood pressure is crucial for patient safety and detecting potential issues like hypertension. However, it is not the primary parameter for evaluating the effectiveness of oxytocin. Blood pressure monitoring is essential for overall health assessment but does not directly relate to the medication's intended effect.

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.