To evaluate the effectiveness of nitroglycerin 0.4 mg SL administered to a client diagnosed with angina pectoris, the nurse should:

Choice A Reason
Increased urine output is not a direct indicator of the effectiveness of nitroglycerin for angina pectoris. Nitroglycerin is a vasodilator used primarily to relieve chest pain by improving blood flow to the heart muscle, not to influence urine production.

Choice B Reason
Asking the client if their chest pain has been relieved is the most direct method of evaluating the effectiveness of nitroglycerin. Relief of chest pain indicates that the medication is working as intended, reducing the ischemia that causes angina.

Choice C Reason
While taking the client's blood pressure is important, especially since nitroglycerin can cause hypotension, it is not the primary method for evaluating the effectiveness of the medication in relieving angina. Blood pressure measurements are more of a safety check to monitor for adverse effects.

Choice D Reason
Ambulation and assessing for the absence of dyspnea can be part of an overall evaluation of the client's cardiovascular status, but they are not specific to evaluating the effectiveness of nitroglycerin for angina relief. Dyspnea may be a symptom of heart failure or other conditions, not specifically angina pectoris.

Choice A reason:
Magnesium sulfate is used in the management of severe preeclampsia primarily for seizure prophylaxis. One of the key side effects of magnesium sulfate is its impact on neuromuscular transmission, leading to diminished deep-tendon reflexes as serum magnesium levels rise. The therapeutic range for anticonvulsant prophylaxis is typically between 5-8 mg/dL. Reflexes may begin to diminish when serum levels reach 8-12 mg/dL, indicating potential magnesium toxicity. Therefore, diminished reflexes are a warning sign to reassess the infusion rate and possibly reduce or discontinue the medication.

Choice B reason:
A respiratory rate of 16 breaths per minute falls within the normal adult range and suggests that the client's respiratory system is not being adversely affected by the magnesium sulfate infusion. Respiratory rate is a critical parameter to monitor during magnesium sulfate therapy, as respiratory depression is a serious side effect of magnesium toxicity. Maintaining a normal respiratory rate indicates that it is safe to continue the infusion at the current rate.

Choice C reason:
While a urine output of 50 mL/hr is on the lower end of the normal range, it is still considered adequate for most adults. In the setting of magnesium sulfate therapy for severe preeclampsia, maintaining adequate urine output is essential for ensuring that the kidneys can excrete the magnesium to prevent accumulation and toxicity. If urine output decreases significantly, it may necessitate reevaluation of the infusion rate or additional interventions to support renal function.

Choice D reason:
A heart rate of 56 beats per minute is slightly bradycardic but may not be clinically significant if the client is asymptomatic. However, magnesium has a direct effect on cardiac function, and high levels can lead to bradycardia and other cardiac conduction abnormalities. It is important to monitor the client's heart rate and rhythm during magnesium sulfate therapy to detect any early signs of cardiac involvement due to magnesium toxicity.