A patient is admited with hypernatremia caused by being stranded on a boat in the Atlantic Ocean for two days without water. What is the patient at risk for developing?

Choice A Reason: This is incorrect because widening of the QRS complex is a sign of severe hyperkalemia, which is a high level of potassium in the blood. A normal QRS complex duration is 0.06 to 0.10 seconds. Hyperkalemia can cause depolarization and repolarization abnormalities in the cardiac cells, leading to delayed ventricular conduction and widened QRS complexes. The nurse should monitor the client's vital signs, electrocardiogram, and serum potassium level, and administer medications or dialysis as ordered.

Choice B Reason: This is incorrect because shortening of P-wave duration is not related to hyperkalemia or polystyrene sulfonate. A normal P-wave duration is 0.06 to 0.12 seconds. The P wave represents atrial depolarization and contraction. Hyperkalemia can cause flatening or disappearance of the P wave, but not shortening. Polystyrene sulfonate is a medication that binds to potassium in the gastrointestinal tract and removes it from the body through feces.

Choice C Reason: This is correct because reduction of T-wave amplitude is a sign of effective treatment of hyperkalemia with polystyrene sulfonate. A normal T-wave amplitude is 0.5 mV or less. The T wave represents ventricular repolarization and relaxation. Hyperkalemia can cause peaked or tented T waves, which indicate increased excitability and risk of ventricular fibrillation. Polystyrene sulfonate lowers the serum potassium level and normalizes the T wave.

Choice D Reason: This is incorrect because restoration of QRS complex amplitude is not related to hyperkalemia or polystyrene sulfonate. A normal QRS complex amplitude is 5 to 30 mm in standard leads and 10 to 20 mm in precordial leads. The QRS complex represents ventricular depolarization and contraction. Hyperkalemia does not affect the QRS complex amplitude significantly, but can cause widening or merging with the T wave in severe cases. Polystyrene sulfonate does not affect the QRS complex amplitude directly, but can prevent further widening or merging.

Choice A: Metabolic alkalosis is incorrect because it is characterized by a high pH and a high HCO3, not a low pH and a normal HCO3. Metabolic alkalosis occurs when there is a loss of metabolic acids or an excess of bicarbonate in the body, such as from vomiting, gastric suctioning, or diuretic therapy.

Choice B: Respiratory acidosis is correct because it is characterized by a low pH and a high PaCO2. Respiratory acidosis occurs when there is impaired gas exchange or hypoventilation, resulting in accumulation of carbon dioxide in the blood. This can be caused by conditions such as chronic obstructive pulmonary disease (COPD), pneumonia, asthma, or chest trauma.

Choice C: Metabolic acidosis is incorrect because it is characterized by a low pH and a low HCO3, not a low pH and a normal HCO3. Metabolic acidosis occurs when there is an excess of metabolic acids in the body, such as lactic acid, ketoacids, or salicylates.

Choice D: Respiratory alkalosis is incorrect because it is characterized by a high pH and a low PaCO2, not a low pH and a high PaCO2. Respiratory alkalosis occurs when there is excessive loss of carbon dioxide through hyperventilation, such as in anxiety, fever, or aspirin overdose.