A nurse is caring for a client who is postpartum. Which of the following findings is an indication for the nurse to administer Rho(D) immune globulin?

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:

This statement is incorrect because Rho(D) immune globulin does not destroy Rh antibodies in a newborn who is Rh-positive. Instead, it acts to prevent the development of Rh antibodies in the mother.

Choice B rationale:

This statement is also incorrect. Rho(D) immune globulin does not destroy Rh antibodies in a woman who is Rh-negative. It is given to Rh-negative women to prevent them from forming Rh antibodies in response to Rh-positive fetal blood during pregnancy.

Choice C rationale:

This is the correct choice. Rho(D) immune globulin is given to Rh-negative women to prevent the formation of Rh antibodies. If an Rh-negative woman is exposed to Rh-positive blood (usually during childbirth), her immune system may recognize the Rh antigen as foreign and start producing Rh antibodies. These antibodies could potentially cross the placenta during a subsequent pregnancy and attack the red blood cells of an Rh-positive fetus, causing hemolytic disease in the newborn. Rho(D) immune globulin helps prevent this sensitization process.

Choice D rationale:

This statement is incorrect. Rho(D) immune globulin does not prevent the formation of Rh antibodies in a newborn who is Rh-positive. Its main purpose is to protect Rh-negative women from forming antibodies that could harm future Rh-positive pregnancies.