A nurse is caring for a client who has acute respiratory failure (ARF). The nurse should monitor the client for which of the following manifestations of this condition? (Select all that apply.)

Choice A Reason: This choice is correct because respiratory acidosis is a condition in which the lungs cannot eliminate enough carbon dioxide (CO2) from the blood, resulting in a high level of CO2 (PaCO2) and a low level of pH. A normal PaCO2 range is 35 to 45 mm Hg, so a value of 50 mm Hg indicates respiratory acidosis.

Choice B Reason: This choice is incorrect because HCO3 (bicarbonate) is a base that helps to buffer the excess acid in the blood. In respiratory acidosis, the kidneys try to compensate by retaining more HCO3 and excreting more hydrogen ions. Therefore, a high level of HCO3 (above 26 mEq/L) would indicate a chronic or compensated respiratory acidosis, not an acute or uncompensated one.

Choice C Reason: This choice is incorrect because pH is a measure of the acidity or alkalinity of the blood. A normal pH range is 7.35 to 7.45, so a value of 7.45 indicates a neutral or slightly alkaline blood, not an acidic one. A low pH (below 7.35) would indicate respiratory acidosis.

Choice D Reason: This choice is incorrect because potassium is an electrolyte that helps to regulate the nerve and muscle function, as well as the fluid balance in the body. In respiratory acidosis, the increased hydrogen ions in the blood may shift into the cells in exchange for potassium, resulting in a high level of potassium (hyperkalemia).

Therefore, a low level of potassium (below 3.5 mEq/L) would indicate hypokalemia, not respiratory acidosis.

Choice A Reason: This is incorrect because preparing for mechanical ventilation is not the priority nursing intervention, as it is an invasive and potentially harmful procedure that should be reserved for clients who have severe respiratory failure and cannot maintain adequate oxygenation with noninvasive methods.

Choice B Reason: This is correct because administering oxygen via face mask is the priority nursing intervention, as it is a noninvasive and effective way to improve oxygenation and reduce hypoxemia in a client who has low PaO2 and SaO2. Oxygen therapy can also decrease the workload of the heart and lungs and prevent further complications.

Choice C Reason: This is incorrect because preparing to administer a sedative is not the priority nursing intervention, as it may worsen the client's respiratory status and mask the signs and symptoms of hypoxemia. Sedatives should be used with caution and only after oxygenation has been optimized.

Choice D Reason: This is incorrect because assessing for indications of pulmonary embolism is not the priority nursing intervention, as it is a diagnostic rather than a therapeutic action. Pulmonary embolism is a possible cause of the client's condition, but it does not address the immediate problem of hypoxemia.