Arterial blood gas (ABG) analysis is a common test that measures oxygen, carbon dioxide, and bicarbonate blood levels. The test provides an assessment of gas exchange processes and acid-base balance. ABGs are usually obtained by puncturing the radial or femoral artery. An arterial line may be placed if frequent ABG sampling and continuous blood pressure monitoring are required.
See also “Arterial access.”
- Procedure: See “ .”
- Partial pressure of oxygen in arterial blood (PaO2) and partial pressure of carbon dioxide (PaCO2) in arterial blood
- Arterial oxygen saturation (SaO2): percentage of hemoglobin binding sites occupied by oxygen
- Base excess: Excess value of base in the blood. Used to identify whether an acid-base imbalance is predominantly a respiratory, metabolic, or a mixed acid-base disorder.
- Standard bicarbonate
- Modern blood gas analyzers also measure: some electrolytes (i.e., sodium, potassium, chloride, calcium), blood glucose, hemoglobin, methemoglobin and carboxyhemoglobin concentrations
- Reference ranges
- Reference range: 65–70%
- Increased tissue oxygen extraction due to decreased oxygen delivery to tissue
- Increased oxygen consumption by tissues
- Inability of hemoglobin to bind to oxygen (e.g., carbon monoxide poisoning)
- Increased SvO2
- Decreased SvO2