Acid-base handling

Question 1

Choose the most appropriate answer from the list.

• Diabetic ketoacidosis
• Intestinal fistula
• Metabolic acidosis
• Metabolic alkalosis
• Poor lung perfusion
• Pyloric stenosis
• Renal failure
• Respiratory acidosis
• Respiratory alkalosis

Causes an increased loss of HCO3-

Answer 1

Intestinal fistula

Question 2

Choose the most appropriate answer from the list.

• Diabetic ketoacidosis
• Intestinal fistula
• Metabolic acidosis
• Metabolic alkalosis
• Poor lung perfusion
• Pyloric stenosis
• Renal failure
• Respiratory acidosis
• Respiratory alkalosis

Causes increased H+ production

Answer 2

Diabetic ketoacidosis

Question 3

Choose the most appropriate answer from the list.

• Diabetic ketoacidosis
• Intestinal fistula
• Metabolic acidosis
• Metabolic alkalosis
• Poor lung perfusion
• Pyloric stenosis
• Renal failure
• Respiratory acidosis
• Respiratory alkalosis

Causes increased H+ loss

Answer 3

Pyloric stenosis

Question 4

Choose the most appropriate answer from the list.

• Diabetic ketoacidosis
• Intestinal fistula
• Metabolic acidosis
• Metabolic alkalosis
• Poor lung perfusion
• Pyloric stenosis
• Renal failure
• Respiratory acidosis
• Respiratory alkalosis

Can be compensated by increased renal excretion of H+

Answer 4

Metabolic acidosis

Question 5

Choose the most appropriate answer from the list.

• Diabetic ketoacidosis
• Intestinal fistula
• Metabolic acidosis
• Metabolic alkalosis
• Poor lung perfusion
• Pyloric stenosis
• Renal failure
• Respiratory acidosis
• Respiratory alkalosis

Can be compensated by hypoventilation

Answer 5

Metabolic alkalosis

Question 6

Choose the most appropriate answer from the list.

• Metabolic Acidosis
• Metabolic Alkalosis
• Respiratory Acidosis
• Respiratory Alkalosis
• Metabolic Acidosis with Respiratory Compensation
• Metabolic Alkalosis with Respiratory Compensation
• Respiratory Acidosis with Metabolic Compensation
• Respiratory Alkalosis with Metabolic Compensation

Gain in bicarbonate ions or loss of H+ ions resulting in raised pH

Answer 6

Metabolic alkalosis

Question 7

Choose the most appropriate answer from the list.

• Metabolic Acidosis
• Metabolic Alkalosis
• Respiratory Acidosis
• Respiratory Alkalosis
• Metabolic Acidosis with Respiratory Compensation
• Metabolic Alkalosis with Respiratory Compensation
• Respiratory Acidosis with Metabolic Compensation
• Respiratory Alkalosis with Metabolic Compensation

24 year old female presents at A&E with a broken ankle. The interpretation of her blood gas results (pH 7.62, PCO2 3.59, PO2 14.1, HCO3 23, Base Excess 0) demonstrates a ____.

Answer 7

Respiratory alkalosis

Question 8

Choose the most appropriate answer from the list.

• Metabolic Acidosis
• Metabolic Alkalosis
• Respiratory Acidosis
• Respiratory Alkalosis
• Metabolic Acidosis with Respiratory Compensation
• Metabolic Alkalosis with Respiratory Compensation
• Respiratory Acidosis with Metabolic Compensation
• Respiratory Alkalosis with Metabolic Compensation

22 year old model is admitted to A&E with weakness and tingling sensations in both hands and feet, and “poor balance”. Patient denies pill ingestion but admits she has been on a strict diet regimen to meet her agency’s expectations. Her ABG results (pH 7.55, PCO2 6.67, PO2 12.0, HCO3 45) demonstrate ____.

Answer 8

Metabolic alkalosis

Question 9

Choose the most appropriate answer from the list.

• Metabolic Acidosis
• Metabolic Alkalosis
• Respiratory Acidosis
• Respiratory Alkalosis
• Metabolic Acidosis with Respiratory Compensation
• Metabolic Alkalosis with Respiratory Compensation
• Respiratory Acidosis with Metabolic Compensation
• Respiratory Alkalosis with Metabolic Compensation

A 40 year old lady with severe chronic back pain (treated aggressively with OTC NSAIDs) for several years was found to have BP 155/95 at her routine GP visit. Her urine dipstick demonstrated ++ protein and increased white blood cells. Her ABG results (pH 7.30, PCO2 4.27, HCO3 15) demonstrate _____.

Answer 9

Metabolic acidosis with respiratory compensation

Question 10

Choose the most appropriate answer from the list.

• Metabolic Acidosis
• Metabolic Alkalosis
• Respiratory Acidosis
• Respiratory Alkalosis
• Metabolic Acidosis with Respiratory Compensation
• Metabolic Alkalosis with Respiratory Compensation
• Respiratory Acidosis with Metabolic Compensation
• Respiratory Alkalosis with Metabolic Compensation

A 45 year old man with a history of solvent (inhalant) abuse presents to A&E complaining of dyspnoea (SPO2 99% on room air). He is tachypnoeic on examination and demonstrates Kussmaul breathing. His ABG (pH 6.95, PCO2 1.20, PO2 17.0, HCO3- 2) demonstrates ___.

Answer 10

Metabolic acidosis with respiratory compensation

Question 11

An elderly patient on the ward has RR 16, HR 65, temp 37.5 degrees C. His blood gases are pH 7.35 (7.35-7.45), pCO2 9.0 (4.7-6 kPa), pO2 8.1(10.0-13.3 kPa), HCO3 45 (22-30). Rank the underlying diseases below in order of likelihood, going from most to least likely:

Pulmonary embolism
Tension pneumothorax
COPD
Hyperventilation
Pneumonia

Answer 11

1. COPD
2. Pneumonia
3. Pulmonary embolism
4. Tension pneumothorax
5. Hyperventilation

This is a picture of respiratory acidosis with metabolic compensation. Hyperventilation would cause alkalosis so is least likely. A tension pneumothorax would not have time to establish compensation so is next least likely. The carbon dioxide is high and the oxygen is low so this is type 2 respiratory failure with no v/q mismatch. while a number of small PEs might result in compensation over time they would give a type 1 picture with low oxygen and normal carbon dioxide. Both pneumonia and COPD might give this blood gas picture but this patient’s vital measurements show no sign of infection so COPD is most likely.

Question 12

Choose the most appropriate answer from the list.

• Metabolic Acidosis
• Metabolic Alkalosis
• Respiratory Acidosis
• Respiratory Alkalosis
• Compensated Respiratory Alkalosis
• Compensated Respiratory Acidosis
• Compensated Metabolic Alkalosis
• Compensated Metabolic Acidosis
• Type I Respiratory Failure
• Type II Respiratory Failure

A 42 year old man with heartburn presents with the following blood gases: pH 7.51, pCO2 5.2kPa, bicarbonate = 30 mmol/l.

Answer 12

Metabolic alkalosis

Question 13

Choose the most appropriate answer from the list.

• Metabolic Acidosis
• Metabolic Alkalosis
• Respiratory Acidosis
• Respiratory Alkalosis
• Compensated Respiratory Alkalosis
• Compensated Respiratory Acidosis
• Compensated Metabolic Alkalosis
• Compensated Metabolic Acidosis
• Type I Respiratory Failure
• Type II Respiratory Failure

65 year old long- term smoker is admitted with drowsiness and confusion. ABG reveals pH 7.36, pO2 7kPa, pCO2 8kPa, bicarbonate 24 mmol/l.

Answer 13

Type II respiratory failure

Question 14

Choose the most appropriate answer from the list.

• Metabolic Acidosis
• Metabolic Alkalosis
• Respiratory Acidosis
• Respiratory Alkalosis
• Compensated Respiratory Alkalosis
• Compensated Respiratory Acidosis
• Compensated Metabolic Alkalosis
• Compensated Metabolic Acidosis
• Type I Respiratory Failure
• Type II Respiratory Failure

Treat with IV sodium bicarbonate

Answer 14

Metabolic acidosis

Question 15

Choose the most appropriate answer from the list.

• Metabolic Acidosis
• Metabolic Alkalosis
• Respiratory Acidosis
• Respiratory Alkalosis
• Compensated Respiratory Alkalosis
• Compensated Respiratory Acidosis
• Compensated Metabolic Alkalosis
• Compensated Metabolic Acidosis
• Type I Respiratory Failure
• Type II Respiratory Failure

24 year old female presents with an aspirin overdose. She appears to be breathing heavily. pH 7.38, pO2 12kPa, pCO2 2.5kPa, bicarbonate 16 mmol/l.

Answer 15

Compensated Metabolic Acidosis

Question 16

Choose the most appropriate answer from the list.

• Metabolic Acidosis
• Metabolic Alkalosis
• Respiratory Acidosis
• Respiratory Alkalosis
• Compensated Respiratory Alkalosis
• Compensated Respiratory Acidosis
• Compensated Metabolic Alkalosis
• Compensated Metabolic Acidosis
• Type I Respiratory Failure
• Type II Respiratory Failure

55 year old male with difficulty breathing is diagnosed with Guillain- Barre syndrome. pH 7.25, pO2 12kPa, pCO2 9kPa, bicarbonate 25 mmol/l.

Answer 16

Respiratory acidosis