A nurse is caring for a client who is experiencing severe nausea and vomiting after a course of chemotherapy. The nurse should monitor the client for which of the following clinical manifestations.

Choice A rationale Respiratory acidosis occurs when there is an accumulation of carbon dioxide in the blood due to hypoventilation or impaired gas exchange. Severe nausea and vomiting involve the loss of fluids and electrolytes from the upper gastrointestinal tract rather than a primary respiratory failure. Since vomiting does not typically cause a retention of CO2, the nurse would not expect to see respiratory acidosis as a direct clinical manifestation of the patient's current gastrointestinal symptoms. Choice B rationale Metabolic alkalosis is a common result of severe vomiting or gastric suctioning. Gastric contents are highly acidic, containing high concentrations of hydrochloric acid. When a patient vomits excessively, they lose large amounts of hydrogen ions and chloride. This loss leads to an excess of bicarbonate in the extracellular fluid, raising the blood pH above 7.45. The nurse must monitor for this because the shift in pH can affect neuromuscular excitability and lead to electrolyte imbalances. Choice C rationale Metabolic acidosis involves a decrease in pH below 7.35 due to an accumulation of metabolic acids or a loss of bicarbonate. While lower gastrointestinal losses like severe diarrhea can lead to metabolic acidosis through the loss of alkaline intestinal secretions, upper gastrointestinal losses through vomiting have the opposite effect. Because the patient is losing acid rather than base, metabolic acidosis is not the expected finding. Normal bicarbonate levels remain between 22 and 28 mEq/L. Choice D rationale Respiratory alkalosis is caused by hyperventilation, which results in the excessive elimination of carbon dioxide and a subsequent increase in blood pH. While pain or anxiety associated with severe nausea might cause a patient to breathe faster, the primary chemical imbalance resulting from the physical loss of stomach acid is metabolic. The direct physiological consequence of losing hydrochloric acid via emesis is the development of a metabolic alkalosis rather than a primary respiratory disturbance.