Which assessment finding indicates that therapeutic drug level of magnesium sulfate has been achieved for a client with severe pregnancy-induced hypertension?

Therapeutic levels of magnesium sulfate are primarily monitored to prevent seizures in clients with severe pregnancy-induced hypertension. One of the expected effects of magnesium sulfate is its ability to act as a central nervous system depressant, which can lead to a reduction in respiratory rate. A decrease in respiratory rate from 24 to 16 breaths per minute indicates that the medication is exerting its calming effects on the body, suggesting that an appropriate therapeutic level has been reached.

When monitoring for magnesium sulfate toxicity, key signs include changes in reflexes, respiratory function, and urinary output. An ideal therapeutic response may include a slight decrease in respiratory rate; however, if the rate becomes too low (<12), it would be concerning.

This context underscores why the other options do not indicate a therapeutic level of magnesium sulfate. For example, hyperactive reflexes (like 4+ reflexes) are a sign of magnesium sulfate toxicity, suggesting that levels are too high. Adequate urinary output is typically >30 mL per hour for those on magnesium, and a rate of 50 mL per hour does not specifically indicate that therapeutic levels have been achieved. Additionally, a decrease in body temperature does not have a direct correlation with magnesium sulfate therapy and is not a