Which laboratory test measures the effectiveness of warfarin?

Digibind is the trade name forantidigoxin, which is an antibody made up of anti-digoxin immunoglobulin fragments.It is thespecific antidoteto digoxin toxicity, which can occur even when the serum digoxin concentration is within the therapeutic range.Digoxin toxicity causes anorexia, nausea, vomiting, neurological symptoms and arrhythmias.

Choice A, Protamine sulfate, is wrong because it is the antidote for heparin overdose, not digoxin toxicity.

Protamine sulfate reverses the anticoagulant effect of heparin by binding to it and forming a stable complex.

Choice B, Acetylcysteine, is wrong because it is the antidote for acetaminophen overdose, not digoxin toxicity.

Acetylcysteine replenishes glutathione, which is depleted by acetaminophen metabolites that cause hepatotoxicity.

Choice D, Vitamin K, is wrong because it is the antidote for warfarin overdose, not digoxin toxicity.

Vitamin K restores the synthesis of clotting factors that are inhibited by warfarin.

Normal ranges for serum digoxin concentration are 0.6 to 1.2 nanomol/L (0.5 to 0.9 nanograms/mL) for heart failure and unknown for atrial fibrillation without heart failure.

Normal ranges for serum potassium level are 3.5 to 5.0 mmol/L and for serum magnesium level are 0.7 to 1.0 mmol/L.

The nurse should contact the provider before administering furosemide because the patient has a low serum potassium level of 2.8 mEq/L, which is below the normal range of 3.5 to 5.0 mEq/L.Furosemide is a diuretic that can cause potassium loss and worsen hypokalemia, which can lead to cardiac arrhythmias, muscle weakness, and fatigue. The nurse should also monitor the patient’s blood pressure, weight, and urine output, as furosemide can lower blood pressure and cause dehydration.

Choice A. Administer medication is wrong because the nurse should not give furosemide without checking with the provider first, as it could be harmful to the patient with low potassium.

Choice C. Hold medication is wrong because the nurse should not withhold furosemide without a valid reason or an order from the provider, as it could cause fluid overload and worsen the patient’s condition.

Choice D. Give potassium supplement is wrong because the nurse should not give potassium supplement without an order from the provider, as it could cause hyperkalemia or interact with other medications.