8.Acid-Base Balance_simplified

A patient is admitted with severe pneumonia. Their ABG results show: pH 7.31, PaCO₂ 52 mmHg, HCO₃⁻ 25 mEq/L. What is your interpretation?

• Compensated metabolic acidosis

• Uncompensated respiratory acidosis

• Partially compensated respiratory alkalosis

• Compensated metabolic alkalosis

Answer explanation

1. The decreased pH (7.31) with elevated PaCO₂ (52 mmHg) and normal HCO₃⁻ (25 mEq/L) indicates respiratory acidosis. The condition is uncompensated because the bicarbonate level hasn't increased to compensate.

Mrs. Johnson is experiencing anxiety-induced hyperventilation. Which ABG values would you expect to see?

• pH 7.48, PaCO₂ 30 mmHg, HCO₃⁻ 22 mEq/L

• pH 7.32, PaCO₂ 50 mmHg, HCO₃⁻ 24 mEq/L

• pH 7.35, PaCO₂ 45 mmHg, HCO₃⁻ 18 mEq/L

• pH 7.30, PaCO₂ 35 mmHg, HCO₃⁻ 16 mEq/L

Answer explanation

1. Hyperventilation causes excessive CO₂ elimination, resulting in respiratory alkalosis characterized by elevated pH, low PaCO₂, and initially normal HCO₃⁻.

A diabetic patient presents with Kussmaul breathing. Their ABG shows: pH 7.25, PaCO₂ 35 mmHg, HCO₃⁻ 15 mEq/L. What condition are they experiencing?

• Respiratory alkalosis

• Metabolic alkalosis

• Respiratory acidosis

• Metabolic acidosis

Answer explanation

1. D) Metabolic acidosis

   Explanation: The low pH with low HCO₃⁻ and compensatory low PaCO₂ (due to Kussmaul breathing) is characteristic of metabolic acidosis, commonly seen in diabetic ketoacidosis.

A patient with a history of kidney problems has ABG results showing: pH 7.50, PaCO₂ 40 mmHg, HCO₃⁻ 32 mEq/L. What condition do these results indicate?

• Respiratory alkalosis

• Metabolic acidosis

• Respiratory acidosis

• Metabolic alkalosis

Answer explanation

1. D) Metabolic alkalosis

   Explanation: The high pH (7.50) with normal PaCO₂ (40 mmHg) and elevated HCO₃⁻ (32 mEq/L) indicates metabolic alkalosis.

A patient is experiencing prolonged vomiting, and their ABG shows: pH 7.58, PaCO₂ 45 mmHg, HCO₃⁻ 41 mEq/L. What condition are they experiencing?

• Metabolic alkalosis

• Respiratory acidosis

• Metabolic acidosis

• Respiratory alkalosis

Answer explanation

1. A) Metabolic alkalosis

   Explanation: Prolonged vomiting causes loss of stomach acid, leading to metabolic alkalosis as indicated by high pH (7.58) and elevated HCO₃⁻ (41 mEq/L).

A young adult is in shock and has ABG results as follows: pH 7.32, PaCO₂ 28 mmHg, HCO₃⁻ 14 mEq/L. What is the primary condition?

• Respiratory alkalosis

• Metabolic acidosis

• Metabolic alkalosis

• Respiratory acidosis

Answer explanation

1. B) Metabolic acidosis

   Explanation: The low pH (7.32) with low HCO₃⁻ (14 mEq/L) and compensatory low PaCO₂ (28 mmHg) is characteristic of metabolic acidosis associated with shock.

A patient with COPD shows the following ABG results: pH 7.36, PaCO₂ 48 mmHg, HCO₃⁻ 30 mEq/L. What do these findings suggest?

• Compensated respiratory acidosis

• Uncompensated metabolic acidosis

• Partially compensated metabolic alkalosis

• Uncompensated respiratory alkalosis

Answer explanation

1. A) Compensated respiratory acidosis

   Explanation: The slightly acidotic pH (7.36) with elevated PaCO₂ (48 mmHg) and compensating elevated HCO₃⁻ (30 mEq/L) suggests compensated respiratory acidosis, common in COPD patients.

An athlete has collapsed during a marathon; their ABG shows: pH 7.15, PaCO₂ 60 mmHg, HCO₃⁻ 24 mEq/L. What is your interpretation?

• Metabolic alkalosis

• Respiratory acidosis

• Metabolic acidosis

• Respiratory alkalosis

Answer explanation

1. B) Respiratory acidosis

   Explanation: The low pH (7.15) with elevated PaCO₂ (60 mmHg) suggests acute respiratory acidosis due to hypoventilation, possibly from physical exhaustion.

A patient taking diuretics has ABG results of: pH 7.49, PaCO₂ 42 mmHg, HCO₃⁻ 34 mEq/L. What acid-base disturbance is present?

• Metabolic alkalosis

• Respiratory acidosis

• Metabolic acidosis

• Respiratory alkalosis

Answer explanation

1. A) Metabolic alkalosis

   Explanation: Diuretics can cause loss of hydrogen ions, leading to metabolic alkalosis. The high pH (7.49) and elevated HCO₃⁻ (34 mEq/L) are indicative of this condition.

A patient in renal failure has the following ABG values: pH 7.18, PaCO₂ 50 mmHg, HCO₃⁻ 16 mEq/L. What condition is indicated?

• Metabolic alkalosis

• Respiratory acidosis

• Metabolic acidosis

• Respiratory alkalosis

Answer explanation

1. C) Metabolic acidosis

   Explanation: The low pH (7.18) with low HCO₃⁻ (16 mEq/L) and compensatory elevated PaCO₂ (50 mmHg) indicates metabolic acidosis, typical in renal failure.