The nurse notices the client's nares have become dry after receiving 4 liters of oxygen via nasal cannula. What is an appropriate intervention?

A. Respiratory acidosis: Respiratory acidosis is characterized by a low pH (<7.35) and elevated PaCO2 (>45 mm Hg), typically due to hypoventilation or impaired gas exchange. In this ABG, the pH is elevated at 7.58 and PaCO2 is within normal limits (37.5 mm Hg), which does not indicate respiratory acidosis.

B. Metabolic alkalosis: Metabolic alkalosis presents with an elevated pH (>7.45) and increased bicarbonate (HCO3 >28 mEq/L). The patient’s pH is 7.58 and HCO3 is 31.2 mEq/L, consistent with metabolic alkalosis. The mild increase in base excess (+6.4) supports metabolic alkalosis, while the near-normal PaCO2 reflects partial respiratory compensation through hypoventilation.

C. Normal ABG results: Normal arterial blood gas values are: pH 7.35–7.45, PaCO2 35–45 mm Hg, HCO3 22–28 mEq/L, PaO2 80–100 mm Hg, and O2 saturation 95–100%. This patient’s ABG shows an elevated pH and HCO3, which are outside normal ranges.

D. Metabolic acidosis: Metabolic acidosis is indicated by a low pH (<7.35) and decreased HCO3 (<22 mEq/L). The patient’s pH is high (7.58) and HCO3 is elevated, which is opposite the pattern seen in metabolic acidosis, making this option inconsistent with the ABG results.

A. Positive Trousseau's sign: Hypocalcemia increases neuromuscular excitability, which can lead to carpopedal spasm when a blood pressure cuff is inflated—a phenomenon known as Trousseau’s sign. This is a classic clinical indicator of low calcium levels and reflects the heightened responsiveness of nerves and muscles to stimulation.

B. Muscle weakness: Although hypocalcemia often causes muscle cramps and spasms, some clients may also experience generalized muscle weakness due to impaired excitation-contraction coupling in skeletal muscles. The decreased availability of calcium for muscle contraction reduces muscle strength while still maintaining increased neuromuscular irritability.

C. Decreased muscle tone: Hypocalcemia typically results in increased, not decreased, muscle tone due to neuromuscular excitability. Reduced muscle tone is more commonly associated with hypercalcemia or neuromuscular disorders that impair contraction rather than low calcium levels.

D. Polyuria: Polyuria is not a direct symptom of hypocalcemia. It is more often associated with hypercalcemia, which can impair renal concentrating ability, or with conditions affecting antidiuretic hormone or renal function. Hypocalcemia primarily affects neuromuscular and cardiac function rather than urine output.

E. Hyporeflexia: Hypocalcemia generally causes hyperreflexia due to increased neuromuscular excitability. Decreased reflexes are more characteristic of hypercalcemia or neuromuscular blockade. Therefore, hyporeflexia would not be expected in a client with low calcium levels.