A nurse is assessing a client who has preeclampsia and received a dose of calcium gluconate to treat magnesium sulfate toxicity. Which of the following findings should the nurse identify as an indication that calcium gluconate was effective?

Choice A rationale Magnesium sulfate toxicity causes central nervous system depression, including respiratory depression. A respiratory rate of 12 breaths/min indicates that the respiratory depression has resolved, suggesting the calcium gluconate, a magnesium antagonist, has effectively reversed the neuromuscular blockade caused by magnesium. A normal respiratory rate is 12-20 breaths/min. Choice B rationale Absent deep tendon reflexes (DTRs) are a sign of magnesium sulfate toxicity due to its depressant effect on neuromuscular transmission. If calcium gluconate were effective, DTRs would return to normal or become less diminished, indicating resolution of magnesium's inhibitory effects on the nervous system. Choice C rationale Slurred speech is a neurological symptom associated with magnesium sulfate toxicity, reflecting central nervous system depression. If calcium gluconate were effective in reversing the toxicity, slurred speech would improve or resolve as the central nervous system depression diminishes. Choice D rationale Urine output of 22 mL/hr indicates oliguria, which can be a sign of worsening preeclampsia or kidney dysfunction, and is not an indicator of effective calcium gluconate administration for magnesium toxicity. Adequate urine output (typically >30 mL/hr) is essential for magnesium excretion and overall renal function.