A nurse is assisting with the care of a client who has severe preeclampsia and is receiving magnesium sulfate IV at 2 g/hr. Which of the following findings indicates that it is safe for the nurse to continue the infusion?
A.
Respiratory rate of 16/min.
B.
Heart rate of 60/min.
C.
Urine output of 50 mL in 4 hr.
D.
Diminished deep-tendon reflexes.
The correct answer and Explanation is :
The correct answer is A. Respiratory rate of 16/min.
Explanation:
Magnesium sulfate is commonly used in the management of severe preeclampsia to prevent seizures. However, it has significant side effects, including respiratory depression, decreased deep-tendon reflexes, and altered cardiac function. Therefore, monitoring for these side effects is crucial to ensure patient safety.
- Respiratory Rate of 16/min:
A normal respiratory rate for adults ranges from 12 to 20 breaths per minute. A rate of 16 breaths per minute is within this normal range and indicates that the patient is not experiencing respiratory depression, a serious side effect of magnesium sulfate toxicity. Respiratory depression typically occurs when magnesium levels are elevated and can lead to inadequate oxygenation and potential respiratory arrest. Therefore, a normal respiratory rate suggests that it is safe to continue the infusion. - Heart Rate of 60/min:
While a heart rate of 60 beats per minute (bradycardia) can be a sign of magnesium toxicity, it is not as immediately critical as other signs. Magnesium sulfate can cause cardiovascular effects such as bradycardia and hypotension. Therefore, close monitoring of heart rate is necessary, but it alone does not definitively indicate whether the infusion should continue. - Urine Output of 50 mL in 4 hr:
Adequate urine output is essential for the safe administration of magnesium sulfate because decreased urine output may indicate impaired renal function and increased risk of magnesium toxicity. An output of 50 mL in 4 hours is quite low (normal output is generally at least 30 mL/hour), which suggests potential renal impairment or fluid retention, warranting caution. - Diminished Deep-Tendon Reflexes:
Diminished deep-tendon reflexes are a classic sign of magnesium toxicity. Normally, reflexes should be brisk, and their reduction indicates elevated magnesium levels and potential toxicity. If reflexes are diminished, it is a critical sign to consider discontinuing or adjusting the infusion.
In summary, while all the listed findings need to be monitored, a normal respiratory rate of 16/min is the safest indicator to continue the magnesium sulfate infusion without immediate risk of respiratory depression.