A nurse is caring for a client who has acute heart failure and is receiving furosemide via IV bolus. The nurse should identify that which of the following findings indicates that the therapy has been effective?

Hyperkalemiais a critical electrolyte disturbance defined by a serum potassium level exceeding 5.0 mEq/L, which alters the resting membrane potentialof excitable tissues. This condition often results from renal failure, metabolic acidosis, or cellular injury, leading to cardiac dysrhythmiasand neuromuscular weakness. Clinical management involves stabilizing the myocardium, shifting potassium intracellularly, and facilitating the definitive excretionof the excess cation from the body to prevent cardiac arrest.

Rationale:

Administering sodium polystyrenerectally is appropriateas it acts as a cation-exchange resin to remove excess potassium from the body. It works in the large intestine by exchanging sodium ions for potassium ions, which are then excreted through the feces. This provides a definitive method for lowering the total body potassiumload in a client with a serum level of 6 mEq/L.

Administering potassium chloride IV is inappropriateand life-threatening for this client because their serum potassium level is already critically elevated at 6 mEq/L. Adding more exogenous potassium would exacerbate the hyperkalemic state, leading to worsening cardiac conduction delays or ventricular fibrillation. The primary goal for this client is potassium reduction, not supplementation or replacement.

Administering insulin IVis appropriatebecause it stimulates the sodium-potassium ATPase pump, facilitating the rapid shift of potassium from the extracellular fluid into the intracellular compartment. This provides a temporary but life-saving reduction in serum potassium levels. Intravenous dextrose is typically co-administered to prevent hypoglycemiaunless the client’s blood glucose is already significantly elevated.

Administering hydralazine IVis inappropriatebecause this client is already experiencing low blood pressure, with a reading of 98/54 mm Hg at 1100. Hydralazine is a direct-acting vasodilatorused to treat hypertension by relaxing vascular smooth muscle. Giving a vasodilator to a hypotensive client would lead to severe hemodynamic collapse and further compromise organ perfusion.

Administering calcium gluconate IVis appropriateas a first-line emergency intervention to stabilize the myocardial cell membrane. While calcium does not lower the serum potassium level, it antagonizes the cardiotoxic effects of hyperkalemia by increasing the threshold potential. This helps prevent lethal arrhythmias, such as the progression from the current peaked T waves to sinusoidal rhythmsor asystole.

Sodium polystyrene sulfonate is a cation-exchange resinutilized in the management of hyperkalemia. It works in the large intestine by exchanging sodium ions for potassium ions, allowing the excess potassiumto be excreted from the body via the feces to prevent cardiac complications.

Rationale:

A.While sodium polystyrene sulfonate can lead to a secondary decrease in calcium levels as a side effect, calcium is not the target of the medication. Monitoring calcium is important for safety, but it does not measure the primary effectiveness of the drug. The drug is specifically formulated to treat potassium imbalances that pose immediate risks to the myocardium.

B.Potassium is the primary laboratory value to monitor because the therapeutic goal of sodium polystyrene sulfonate is to lower serum potassium levels. Effectiveness is confirmed when the lab results show a return toward the normal range of 3.5 to 5.0 mEq/L. Since high potassium can cause fatal arrhythmias, this lab provides the definitive proof of the medication's clinical success.

C.Sodium levels may increase during therapy because the resin releases sodium in exchange for potassium, but this is a side effect rather than a measure of efficacy. Monitoring sodium is necessary to prevent hypernatremia and fluid retention, especially in heart failure patients. However, the nurse prioritizes the potassium level to ensure the life-threatening hyperkalemia has been resolved.

D.Magnesium levels are not the primary focus for evaluating the effectiveness of this exchange resin. While electrolyte shifts can occur broadly during diuresis or bowel clear-out, sodium polystyrene sulfonate has a specific affinity for potassium. The nurse should monitor magnesium for general electrolyte balance, but it does not serve as a benchmark for the medication's intended therapeutic action.