What condition do these results indicate? A nurse is reviewing arterial blood gas lab values on her newly admitted elderly client. The ABG results are as follows: pH 7.21, PaCO2 50, HCO3 26.

A) Spironolactone:
Spironolactone is a potassium-sparing diuretic commonly used in the treatment of heart failure. Unlike other diuretics, spironolactone works by antagonizing aldosterone, a hormone that promotes sodium and water retention and potassium excretion. By blocking aldosterone's action, spironolactone prevents the kidneys from excreting potassium, thus increasing potassium levels in the blood (hyperkalemia). Additionally, spironolactone can lead to hyponatremia (low sodium levels), as it also causes the kidneys to retain sodium and water, diluting sodium levels in the blood.

B) Furosemide:
Furosemide, a loop diuretic, is typically used in heart failure to remove excess fluid. It works by inhibiting the reabsorption of sodium, chloride, and potassium in the loop of Henle, which increases urine output. While furosemide can cause hypokalemia (low potassium levels) due to the increased excretion of potassium, it does not typically cause hyperkalemia.

C) Hydrochlorothiazide:
Hydrochlorothiazide is a thiazide diuretic, which works by inhibiting sodium and chloride reabsorption in the distal convoluted tubule of the kidney, leading to increased urine production. Thiazide diuretics can cause hypokalemia (low potassium levels) and hyponatremia (low sodium levels) due to the enhanced excretion of both electrolytes.

D) Metolazone:
Metolazone is also a thiazide-like diuretic that works similarly to hydrochlorothiazide. It can cause hypokalemia and hyponatremia, but like hydrochlorothiazide, it does not typically cause hyperkalemia. Metolazone is more potent than hydrochlorothiazide but still does not carry the risk of hyperkalemia like spironolactone does.

A) Respiratory acidosis:
This condition is characterized by an increase in PaCO2 and a decrease in pH, which is exactly what is seen in these ABG results. The pH of 7.21 indicates acidosis (normal pH range is 7.35–7.45), and the PaCO2 of 50 is elevated (normal PaCO2 range is 35–45 mmHg), indicating that carbon dioxide retention is contributing to the acidosis. In respiratory acidosis, the lungs are unable to adequately expel CO2, leading to an accumulation of CO2 in the blood, which decreases the pH. The HCO3 (bicarbonate) is within normal range (22–28 mEq/L), suggesting that there has not yet been compensation by the kidneys, which would typically increase bicarbonate levels to buffer the acidosis.

B) Metabolic alkalosis:
Metabolic alkalosis is characterized by an elevated pH (above 7.45) and an elevated HCO3 (above 28 mEq/L). In this case, the pH is low (7.21), and the bicarbonate level (HCO3) is normal (26), so metabolic alkalosis is not the correct diagnosis.

C) Respiratory alkalosis:
Respiratory alkalosis occurs when there is decreased PaCO2 (below 35 mmHg) and an elevated pH (above 7.45), typically due to hyperventilation. Since the PaCO2 is elevated (50 mmHg) in this case, it rules out respiratory alkalosis.

D) Metabolic acidosis:
Metabolic acidosis is characterized by a low pH (below 7.35) and a low HCO3 (below 22 mEq/L). While the pH is low in this case, the HCO3 is normal (26 mEq/L), which suggests that the acidosis is not metabolic in origin. Metabolic acidosis would typically show a low bicarbonate level, indicating that the kidneys are not able to compensate effectively.