The nurse is caring for a client with respiratory insufficiency. The arterial blood gas (ABG) results indicate a pH of 7.50 and a PaCO2 of 30 mm Hg, and the nurse concludes that the client is experiencing respiratory alkalosis. Which additional laboratory value would the nurse expect to note in this client?

Choice A reason: Stroke is not a cause of hyponatremia, but rather a possible complication of it. Hyponatremia is a condition where the sodium level in the blood is too low, which can affect the brain function and cause symptoms such as confusion, seizures, or coma. Stroke is a condition where the blood supply to a part of the brain is interrupted, which can cause brain damage and neurological deficits.

Choice B reason: Dehydration is not a cause of hyponatremia, but rather a cause of hypernatremia. Dehydration is a condition where the body loses more fluids than it takes in, which can affect the blood volume and the electrolyte balance. Dehydration can cause hypernatremia, which is a condition where the sodium level in the blood is too high, which can also affect the brain function and cause symptoms such as thirst, dry mouth, or lethargy.

Choice C reason: Increased secretion of aldosterone is not a cause of hyponatremia, but rather a cause of hypokalemia. Aldosterone is a hormone that regulates the sodium and potassium levels in the body by increasing the reabsorption of sodium and the excretion of potassium in the kidneys. Increased secretion of aldosterone can cause hypokalemia, which is a condition where the potassium level in the blood is too low, which can affect the muscle and nerve function and cause symptoms such as weakness, cramps, or arrhythmias.

Choice D reason: Congestive heart failure (CHF) is a cause of hyponatremia, as it is a condition where the heart is unable to pump enough blood to meet the body's needs. This can lead to fluid retention and edema, which can dilute the sodium level in the blood and cause hyponatremia. CHF can also stimulate the release of antidiuretic hormone (ADH), which increases the reabsorption of water in the kidneys and further lowers the sodium level in the blood.

Choice A reason: This is incorrect because normal saline is not indicated for this client. Normal saline is a isotonic solution that does not alter the acid-base balance. The client has respiratory alkalosis, which is caused by hyperventilation and results in a high pH and a low PaCO2.

Choice B reason: This is incorrect because Allen's test is not relevant for this client. Allen's test is a test to assess the patency of the radial and ulnar arteries before performing an arterial blood gas (ABG) sampling or cannulation. The client already has ABG results, so there is no need to perform Allen's test.

Choice C reason: This is incorrect because increasing breathing would worsen the client's condition. Increasing breathing would cause the client to exhale more carbon dioxide, which would lower the PaCO2 and raise the pH even more. This would increase the severity of respiratory alkalosis.

Choice D reason: This is correct because slowing down breathing would help the client to correct the respiratory alkalosis. Slowing down breathing would allow the client to retain more carbon dioxide, which would increase the PaCO2 and lower the pH. This would bring the acid-base balance closer to normal.