An anxious adult patient is experiencing a respiratory rate of 40 breaths/min. The most appropriate intervention that the nurse could do is to instruct the patient to:

Choice A reason: Producing phosphate buffers is not the main function of the kidneys in response to acid-base disturbances. Phosphate buffers are mainly found in the intracellular fluid and the urine, where they help to maintain the pH by binding or releasing hydrogen ions.

Choice B reason: Adjusting PaCO2 levels is not the function of the kidneys, but rather the function of the lungs in response to acid-base disturbances. The lungs regulate the PaCO2 levels by increasing or decreasing the rate and depth of respiration, which affects the amount of carbon dioxide exhaled.

Choice C reason: Producing protein buffers is not the function of the kidneys, but rather the function of the cells and the plasma in response to acid-base disturbances. Protein buffers are the most abundant and versatile buffers in the body, as they can act as acids or bases by donating or accepting hydrogen ions.

Choice D reason: Excreting or reabsorbing hydrogen or bicarbonate is the main function of the kidneys in response to acid-base disturbances. The kidneys regulate the HCO3- levels by either reabsorbing it from the filtrate or generating it from carbon dioxide and water. The kidneys also regulate the hydrogen ion levels by either excreting it into the urine or exchanging it for sodium ions.

Choice A reason: Sodium (Na+) imbalance can cause neurological symptoms such as confusion, seizures, or coma, but not abdominal pain or urinary retention.

Choice B reason: Calcium (Ca2+) imbalance can cause abdominal pain, urinary retention, and confusion, as well as muscle weakness, bone pain, and cardiac arrhythmias. These signs are the result of an inadequate supply of calcium, which is essential for nerve and muscle function, as well as bone health.

Choice C reason: Chloride (Cl-) imbalance can cause acid-base disorders such as metabolic acidosis or alkalosis, but not abdominal pain, urinary retention, or confusion.

Choice D reason: Phosphates (PO4^3^-) imbalance can cause bone and muscle problems, such as rickets, osteomalacia, or tetany, but not abdominal pain, urinary retention, or confusion.

Choice E reason: Potassium (K+) imbalance can cause cardiac and neuromuscular symptoms, such as arrhythmias, palpitations, muscle weakness, or paralysis, but not abdominal pain, urinary retention, or confusion.