A nurse is assessing a client who has heart failure and is taking digoxin. Which of the following findings should the nurse identify as an early indication of medication toxicity?

Choice A Reason:
Serum osmolarity 310 mOsm/L is incorrect. Serum osmolarity measures the concentration of particles in the blood. While an elevated serum osmolarity might indicate dehydration, it's not a direct indicator of the effectiveness of treatment. It signifies the concentration of solutes in the blood rather than reflecting hydration improvement after treatment.
Choice B Reason:
Serum hematocrit 55%m is incorrect. Elevated hematocrit levels can occur in dehydration because of hemoconcentration (an increase in the concentration of red blood cells due to reduced fluid volume). However, similar to serum osmolarity, while it can indicate dehydration, it doesn't specifically reflect the effectiveness of treatment.
To determine effective treatment of dehydration, the nurse should consider the laboratory values that reflect hydration status:
Choice C Reason:
Urine specific gravity 1.020 is correct. Urine specific gravity measures the concentration of solutes in the urine, indicating the kidneys' ability to concentrate urine. A higher specific gravity (typically above 1.020) suggests more concentrated urine, which can indicate dehydration. As hydration improves, the urine becomes less concentrated, so a decrease in urine specific gravity toward the normal range (around 1.010-1.020) indicates effective rehydration and improved kidney function in retaining fluids.
Choice D Reason:
BUN 28 mg/dL is incorrect. Blood urea nitrogen (BUN) levels can also rise in dehydration due to reduced kidney perfusion. However, like serum osmolarity and hematocrit, while it can indicate dehydration, it doesn't directly show the effectiveness of treatment or the improvement in hydration status after treatment.

Choice A Reason:
Visual disturbances is the correct findings. In individuals taking digoxin, visual disturbances such as blurred or yellow-tinted vision can indicate early signs of medication toxicity. This symptom often requires prompt medical attention, as it can precede more severe complications.
Choice B Reason:
Sudden weight gain is not correct. While weight gain can be a symptom of worsening heart failure, it's not typically associated specifically with digoxin toxicity. It's more commonly related to fluid retention in heart failure.
Choice C Reason:
Potassium 4.4 mEq/L is not correct. This potassium level is within the normal range. Digoxin toxicity can be exacerbated by low potassium levels, but a normal potassium level doesn't directly indicate digoxin toxicity.
Choice D Reason:
Insomnia is not a typical early sign of digoxin toxicity. It's more commonly associated with issues like difficulty sleeping rather than being a direct symptom of digoxin toxicity.