A nurse is caring for a client admitted to the intensive care unit for a cardiac dysrhythmia. The nurse understands the prescribed calcium channel blocker has which of the following mechanisms of action?
Acts on the beta cells within the heart and lungs to regulate cardiac rhythm
Increases heart rate and increases myocardial contractility
Reduces the contractility and conductivity of the heart
Increase oxygen to the systemic circulation
The Correct Answer is C
A) "Acts on the beta cells within the heart and lungs to regulate cardiac rhythm.": This statement is incorrect because calcium channel blockers do not primarily act on beta cells. Instead, they block calcium channels in cardiac and smooth muscle, which affects heart contractility and conductivity.
B) "Increases heart rate and increases myocardial contractility.": Calcium channel blockers typically do the opposite; they decrease heart rate and myocardial contractility by inhibiting calcium entry into the heart muscle cells. Therefore, this statement does not accurately describe their mechanism of action.
C) "Reduces the contractility and conductivity of the heart.": This statement accurately reflects the action of calcium channel blockers. By blocking calcium entry, these medications decrease myocardial contractility and slow down electrical conduction through the heart, which can help manage dysrhythmias.
D) "Increase oxygen to the systemic circulation.": While calcium channel blockers can improve blood flow and reduce myocardial oxygen demand by decreasing heart workload, their primary action does not directly focus on increasing oxygen delivery to systemic circulation. Their primary role is in managing heart contractility and rhythm.
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Correct Answer is A
Explanation
A) Heparin induced thrombocytopenia (HIT): Argatroban is an indirect thrombin inhibitor specifically used for anticoagulation in patients with HIT. This condition involves a significant drop in platelet counts due to heparin therapy, and argatroban is an appropriate alternative for preventing thrombosis in these patients.
B) Ventricular Dysfunction: While managing anticoagulation may be important in patients with ventricular dysfunction, this condition does not specifically necessitate the use of argatroban. Other anticoagulants may be used based on the clinical situation.
C) Myocardial infarction: Although anticoagulation may be warranted in the setting of a myocardial infarction, argatroban is not specifically indicated for this condition. Other antithrombotic therapies, such as aspirin or heparin, are more commonly used.
D) Hepatotoxicity: Argatroban is metabolized in the liver, so caution is warranted in patients with liver dysfunction. Hepatotoxicity itself would not be a reason to use argatroban; rather, it may require close monitoring or adjustment of dosage.
Correct Answer is D
Explanation
A) Pancytopenia: While some medications can cause pancytopenia, it is not a common or direct side effect of alteplase. This condition involves a reduction in red blood cells, white blood cells, and platelets, and is not typically associated with thrombolytics.
B) Hypertension: Alteplase is not known to cause hypertension. In fact, the goal of administering alteplase in the context of a pulmonary embolism is to dissolve the clot and restore normal blood flow, which may help stabilize blood pressure.
C) Hypokalemia: This condition, characterized by low potassium levels, is not a common side effect of alteplase. There are other medications that may cause electrolyte imbalances, but alteplase itself is not typically linked to hypokalemia.
D) Internal bleeding: This is a significant risk associated with alteplase, as it is a thrombolytic agent that dissolves clots. The nurse should closely monitor for signs of internal bleeding, such as changes in vital signs, unexplained bruising, or blood in urine or stool. This is the most critical side effect to assess for in a client receiving alteplase