2. Arterial blood gas

Question 1

What is arterial blood gas (ABG) analysis?

Answer 1

It is a test that measures O2, CO2, and HCO3- levels in the blood and provides an assessment of gas exchange process and acid-base balance.

Question 2

What are the indications for ABG analysis?

Answer 2

It is indicated for
- acute/chronic pulmonary diseases,
- cardiovascular diseases,
- acute respiratory failure,
- metabolic/respiratory abnormalities,
- exercise test,
- sleep disorders,
- severely ill patients

Question 3

What symptoms should prompt an ABG analysis?

Answer 3

Dyspnea, tachypnea, tachycardia, and increased respiratory work should prompt an ABG analysis.

Question 4

What are the measured parameters in ABG analysis?

Answer 4

Partial pressure of O2 (PaO2) and partial pressure of CO2 (PaCO2) in arterial blood, arterial oxygen saturation (SaO2), pH level, base excess and standard HCO3-.

Question 5

What is the reference range for pH in arterial blood?

Answer 5

The reference range for pH in arterial blood is 7.35-7.45.

Question 6

What is the reference range for PaCO2 in arterial blood?

Answer 6

The reference range for PaCO2 in arterial blood is 35-45mmHg.

Question 7

What is the normal range for resting PaO2 in arterial blood?

Answer 7

The normal range for resting PaO2 in arterial blood is >80mmHg (75-100mmHg).

Question 8

What is the reference range for HCO3- in arterial blood?

Answer 8

The reference range for HCO3- in arterial blood is 22-26mEq/L.

Question 9

What is the reference range for SaO2 in arterial blood?

Answer 9

The reference range for SaO2 in arterial blood is >95%.

Question 10

What is the reference range for base excess in arterial blood?

Answer 10

The reference range for base excess in arterial blood is -2 to +2 mmol/L.

Question 11

What is the purpose of measuring base excess in arterial blood?

Answer 11

Base excess is used to identify whether an acid-base imbalance is respiratory/metabolic/mixed acid-base disorder.

Question 12

What are the types of respiratory failure?

Answer 12

The types of respiratory failure are hypoxemic respiratory failure (type 1) and hypercapnic respiratory failure (type 2).

Question 13

What are the characteristics of hypercapnic respiratory failure?

Answer 13

Hypercapnic respiratory failure is characterized by an increase in PaCO2 and a decrease in PaO2.