Diagnostic Focus in Arterial Blood Gas (ABG) Analysis - Respiratory Therapist Reviewer

The Respiratory Therapist Licensure Examination in the Philippines assesses candidates' knowledge and competencies in key diagnostic procedures, including Arterial Blood Gas (ABG) analysis. ABG is an essential diagnostic tool that evaluates the acid-base balance, ventilation efficiency, and oxygenation status of patients. A comprehensive understanding of ABG is crucial for passing the board exam and excelling in clinical practice.

The review covers core topics such as the interpretation of critical parameters, including pH, PaCO2 (partial pressure of carbon dioxide), PaO2 (partial pressure of oxygen), HCO3- (bicarbonate), and SaO2 (oxygen saturation). Candidates must be adept at identifying normal and abnormal values and recognizing the implications of these results for respiratory function.

One of the key components of ABG analysis is assessing acid-base balance. Review materials should emphasize the differentiation between respiratory and metabolic acidosis or alkalosis and the compensatory mechanisms involved. Proper identification of these conditions is essential for understanding patient pathophysiology and formulating appropriate interventions.

The review also includes case studies to help candidates apply theoretical concepts in clinical scenarios, such as identifying respiratory or metabolic imbalances and determining the severity of oxygenation issues. These practical applications help candidates prepare for real-world challenges they may encounter as licensed respiratory therapists.

Mastering ABG analysis ensures that examinees can contribute effectively to patient care, particularly in critical care settings where respiratory management is essential. By focusing on diagnostic interpretation, acid-base assessment, and disorder identification, the ABG review equips aspiring respiratory therapists with the knowledge and analytical skills necessary to succeed in the licensure examination and their professional practice.

RESPIRATORY THERAPIST REVIEWER

Welcome to our Respiratory Therapist Reviewer. In this session, you'll have the opportunity to test your understanding of key concepts in Arterial Blood Gas (ABG) Analysis. The quiz consists of multiple-choice questions covering various topics. Pay close attention to each question and select the best answer. After completing the exam, check the video or the answer key and explanations at the last part.

Basic Interpretation of ABG Values

1. Which of the following is the normal range for arterial pH?
A. 7.25 – 7.35
B. 7.35 – 7.45
C. 7.45 – 7.55
D. 7.30 – 7.40

2. A normal arterial PaCO2 level falls within which range?
A. 25 – 35 mmHg
B. 35 – 45 mmHg
C. 45 – 55 mmHg
D. 55 – 65 mmHg

3. Which ABG parameter is most useful in assessing metabolic disorders?

A. pH
B. PaCO2
C. HCO3-
D. PaO2

4. What is the primary buffer system in the blood that regulates pH?
A. Carbonic acid-bicarbonate buffer
B. Phosphate buffer system
C. Protein buffer system
D. Renal buffer system

5. A patient has the following ABG results: pH = 7.48, PaCO2 = 32 mmHg, HCO3- = 24 mEq/L. What is the diagnosis?

A. Metabolic alkalosis
B. Respiratory acidosis
C. Respiratory alkalosis
D. Metabolic acidosis

Assessment of Acid-Base Balance

6. What is the most likely cause of respiratory acidosis?
A. Hyperventilation
B. Hypoventilation
C. Diarrhea
D. Vomiting

7. Which condition is commonly associated with metabolic acidosis?
A. Chronic obstructive pulmonary disease (COPD)
B. Diabetic ketoacidosis (DKA)
C. Hyperventilation syndrome
D. Pulmonary embolism

8. What compensatory mechanism occurs in metabolic acidosis?

A. Hypoventilation
B. Hyperventilation
C. Increased renal excretion of hydrogen ions
D. Decreased renal reabsorption of bicarbonate

9. A patient with severe vomiting may develop which acid-base disorder?
A. Respiratory acidosis
B. Metabolic acidosis
C. Metabolic alkalosis
D. Respiratory alkalosis

10. What is the most common cause of respiratory alkalosis?
A. Hypoventilation
B. Hyperventilation
C. Diabetic ketoacidosis
D. Renal failure

Identification of Respiratory and Metabolic Disorders

11. A patient’s ABG results show pH = 7.28, PaCO2 = 52 mmHg, HCO3- = 24 mEq/L. What is the most likely disorder?

A. Respiratory alkalosis
B. Metabolic acidosis
C. Respiratory acidosis
D. Metabolic alkalosis

12. Which ABG abnormality is expected in a patient with an opioid overdose?
A. Respiratory alkalosis
B. Respiratory acidosis
C. Metabolic acidosis
D. Metabolic alkalosis

13. Which metabolic condition is associated with high anion gap metabolic acidosis?
A. Renal failure
B. Hyperaldosteronism
C. Chronic vomiting
D. COPD

14. A patient has a pH of 7.55 and HCO3- of 30 mEq/L. What is the most likely diagnosis?

A. Respiratory acidosis
B. Metabolic alkalosis
C. Metabolic acidosis
D. Respiratory alkalosis

15. What is the primary compensatory response to metabolic alkalosis?
A. Increased renal bicarbonate excretion
B. Hyperventilation
C. Hypoventilation
D. Increased hydrogen ion excretion

Oxygenation and ABG Interpretation

16. A patient with PaO2 of 50 mmHg is experiencing which condition?
A. Normal oxygenation
B. Hyperoxia
C. Metabolic acidosis
D. Hypoxemia

17. Which ABG value is most useful in assessing ventilation?
A. PaO2
B. HCO3-
C. PaCO2
D. SaO2

18. What is the normal range for arterial oxygen saturation (SaO2)?

A. 70 – 80%
B. 80 – 85%
C. 90 – 95%
D. 95 – 100%

19. Which of the following conditions leads to respiratory failure Type I?

A. Hypercapnia with normal oxygenation
B. Hypoxemia without hypercapnia
C. Hypoxemia with hypercapnia
D. Normal PaO2 and PaCO2

Compensatory Mechanisms and Clinical Application

20. Which of the following best describes the compensatory response in respiratory acidosis?
A. The lungs increase ventilation to blow off CO2
B. The kidneys excrete hydrogen ions and retain bicarbonate
C. The kidneys excrete bicarbonate and retain hydrogen ions
D. The lungs decrease ventilation to retain CO2

21. A patient’s ABG results show pH = 7.29, PaCO2 = 38 mmHg, HCO3- = 18 mEq/L. What is the most likely disorder?
A. Respiratory acidosis
B. Respiratory alkalosis
C. Metabolic acidosis
D. Metabolic alkalosis

22. Which ABG finding is most commonly seen in chronic obstructive pulmonary disease (COPD)?

A. Low pH, high PaCO2, high HCO3-
B. High pH, low PaCO2, low HCO3-
C. Normal pH, high PaCO2, high HCO3-
D. Normal pH, low PaCO2, low HCO3-

23. A patient with a severe asthma attack is likely to exhibit which ABG result initially?

A. pH = 7.30, PaCO2 = 50 mmHg
B. pH = 7.50, PaCO2 = 30 mmHg
C. pH = 7.35, PaCO2 = 40 mmHg
D. pH = 7.25, PaCO2 = 25 mmHg

24. A patient with renal failure and a bicarbonate level of 16 mEq/L is most likely to have which condition?
A. Respiratory acidosis
B. Metabolic acidosis
C. Respiratory alkalosis
D. Metabolic alkalosis

Oxygenation and Clinical Cases

25. A PaO2 value of 58 mmHg in an ABG sample indicates which condition?
A. Normal oxygenation
B. Hyperoxia
C. Mild hypoxemia
D. Severe hypoxemia

26. Which ABG value is most important in assessing ventilation efficiency?
A. PaO2
B. HCO3-
C. PaCO2
D. SaO2

27. A patient is given excessive oxygen therapy and develops a PaO2 of 180 mmHg. What is this condition called?

A. Hypercapnia
B. Hypoxia
C. Hyperoxia
D. Respiratory acidosis

28. Which condition is characterized by a normal PaCO2 but a low PaO2?

A. Type 1 respiratory failure
B. Type 2 respiratory failure
C. Metabolic acidosis
D. Metabolic alkalosis

29. What is the primary cause of respiratory alkalosis in critically ill patients?

A. Hyperventilation
B. Hypoventilation
C. Metabolic acidosis
D. Ketoacidosis

30. Which ABG pattern is expected in a patient with prolonged diarrhea?

A. Low pH, low HCO3-, normal PaCO2

B. High pH, high HCO3-, high PaCO2
C. Normal pH, normal HCO3-, high PaCO2
D. Low pH, high HCO3-, normal PaCO2

ANSWER KEY HERE