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?
U waves.
Absent P waves.
Elevated T waves.
Inverted QRS complexes.
The Correct Answer is C
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.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
Choice A reason:
pH 7.50, PaCO2 40 mm Hg, HCO3- 30 mEq/L. This choice is correct because it shows a high pH, a normal PaCO2, and a high HCO3-, which are consistent with metabolic alkalosis. Metabolic alkalosis occurs when there is a loss of acid or a gain of base in the body fluids, such as from prolonged nasogastric suctioning. The kidneys try to compensate by excreting more bicarbonate, but this process is slow and incomplete.
Choice B reason:
pH 7.35, PaCO2 35 mm Hg, HCO3- 24 mEq/L. This choice is incorrect because it shows normal values for pH, PaCO2, and HCO3-, which indicate no acid-base imbalance. A client with metabolic alkalosis would have an elevated pH and bicarbonate level.
Choice C reason:
pH 7.25, PaCO2 50 mm Hg, HCO3- 26 mEq/L. This choice is incorrect because it shows a low pH, a high PaCO2, and a normal HCO3-, which are consistent with respiratory acidosis. Respiratory acidosis occurs when there is impaired gas exchange or hypoventilation, leading to an accumulation of carbon dioxide in the blood. The kidneys try to compensate by retaining more bicarbonate, but this process is slow and incomplete.
Choice D reason:
pH 7.30, PaCO2 30 mm Hg, HCO3- 18 mEq/L. This choice is incorrect because it shows a low pH, a low PaCO2, and a low HCO3-, which are consistent with metabolic acidosis. Metabolic acidosis occurs when there is a gain of acid or a loss of base in the body fluids, such as from diabetic ketoacidosis or diarrhea. The lungs try to compensate by increasing the rate and depth of breathing to expel more carbon dioxide, but this process is fast and limited.
Correct Answer is C
Explanation
Choice A reason: Sodium. Sodium is not affected by serum phosphate level in chronic kidney disease (CKD) patients. Sodium level is mainly regulated by the renin-angiotensin-aldosterone system and the antidiuretic hormone. Sodium level can be altered by fluid intake, fluid loss, diuretics, or salt restriction, but not by phosphate level.
Choice B reason:
Magnesium. Magnesium is also not affected by serum phosphate level in CKD patients. Magnesium level is mainly influenced by dietary intake, intestinal absorption, renal excretion, and exchange with bone and soft tissues. Magnesium level can be altered by malnutrition, malabsorption, diarrhea, vomiting, diuretics, or alcoholism, but not by phosphate level.
Choice C reason:
Calcium. Calcium is the correct answer because calcium and phosphate have an inverse relationship in the body. When serum phosphate level is elevated, as in CKD patients, serum calcium level tends to decrease. This is because high phosphate level binds to calcium and forms insoluble complexes that are deposited in soft tissues and bones. This reduces the amount of free calcium in the blood and triggers the secretion of parathyroid hormone (PTH), which further lowers the calcium level by increasing its excretion in the urine.
Choice D reason:
Bicarbonate. Bicarbonate is not directly affected by serum phosphate level in CKD patients. Bicarbonate level is mainly determined by the acid-base balance in the body. Bicarbonate level can be altered by metabolic acidosis or alkalosis, respiratory acidosis or alkalosis, renal failure, or diarrhea, but not by phosphate level.
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