A patient has been admitted with a potassium level of 6.8 mEq/L. The nurse would expect which of the following electrocardiogram (ECG) changes as a result of this laboratory value?

Choice A reason:

Decreased urine specific gravity indicates improvement in hydration status. Urine specific gravity is a measure of the concentration of solutes in the urine. It reflects the ability of the kidney to concentrate or dilute urine. A high urine specific gravity (>1.030) indicates concentrated urine, which can be caused by dehydration, reduced renal blood flow, or increased fluid loss. A low urine specific gravity (<1.010) indicates diluted urine, which can be caused by overhydration, diuretic use, or impaired renal function. A normal urine specific gravity ranges from 1.010 to 1.030.

Choice B reason:

Increased hematocrit level indicates worsening of dehydration. Hematocrit is the percentage of red blood cells in the total blood volume. It is affected by the plasma volume and the number of red blood cells. A high hematocrit (>47% for males and >42% for females) indicates hemoconcentration, which can be caused by dehydration, polycythemia, or hypoxia. A low hematocrit (<37% for males and <32% for females) indicates hemodilution, which can be caused by overhydration, anemia, or hemorrhage. A normal hematocrit ranges from 37% to 47% for males and 32% to 42% for females.

Choice C reason:

Decreased skin turgor indicates persistent dehydration. Skin turgor is the elasticity of the skin that reflects its hydration status. It is assessed by pinching a fold of skin on the chest, abdomen, or forearm and releasing it. Normally, the skin should return to its original position in less than 3 seconds. If the skin remains elevated or takes longer to return, it indicates poor skin turgor, which can be caused by dehydration, aging, or edema.

Choice D reason:

Increased serum osmolarity indicates worsening of dehydration. Serum osmolarity is a measure of the concentration of solutes in the blood plasma. It reflects the balance between water and electrolytes in the body fluids. A high serum osmolarity (>300 mOsm/kg) indicates hyperosmolarity, which can be caused by dehydration, hypernatremia, hyperglycemia, or mannitol infusion. A low serum osmolarity (<280 mOsm/kg) indicates hypoosmolarity, which can be caused by overhydration, hyponatremia, syndrome of inappropriate antidiuretic hormone secretion (SIADH), or diuretic use. A normal serum osmolarity ranges from 280 to 300 mOsm/kg.

Choice A reason:

U waves are not a sign of high potassium level, but rather of low potassium level (hypokalemia) Hypokalemia can cause ST segment depression, T wave flattening or inversion, and prominent U waves.

Choice B reason:

Absent P waves are not a sign of high potassium level, but rather of a severe conduction block or atrial fibrillation. High potassium level can cause P wave widening or flattening, and PR prolongation, but not complete disappearance of P waves.

Choice C reason:

Elevated T waves are the most common and earliest sign of high potassium level (hyperkalemia) Hyperkalemia can cause tall, peaked, symmetric T waves that may merge with the QRS complex. This is the correct answer.

Choice D reason:

Inverted QRS complexes are not a sign of high potassium level, but rather of ventricular arrhythmias or myocardial infarction. High potassium level can cause QRS widening and bizarre QRS morphology, but not inversion.