Arterial Blood Gas (ABG) measurement is a crucial diagnostic tool used to assess the levels of oxygen and carbon dioxide in a person’s blood. This test provides valuable insights into the acid-base balance, indicating the functioning of the lungs, kidneys, and heart. In this article, we explore the significance of ABG, its purpose, and the process involved.
ABG Measurement of Oxygen and Carbon Dioxide
- Oxygen is essential for every cell in the body to thrive, and ABG measures the oxygen and carbon dioxide levels in the bloodstream.
- Through the process of gas exchange, the lungs transfer oxygen into the blood while removing carbon dioxide during exhalation.
Reasons for Arterial Blood Gas Test
- Diagnosing and monitoring severe breathing and lung conditions like asthma, cystic fibrosis, and chronic obstructive pulmonary disease (COPD).
- Evaluating the effectiveness of prescribed lung medications.
- Assessing the need for supplemental oxygen or additional respiratory support.
- Analyzing pH levels to detect conditions such as kidney failure, serious illnesses, specific toxic ingestions, complications of diabetes, or untreated sleep apnea.
Process of Arterial Blood Gas
- The sample is usually taken from the wrist artery, but it can also be collected from the femoral artery or inside the arm above the elbow crease.
- The healthcare professional performing the test ensures normal blood flow to the hand through a method called the Allen test.
- After cleaning the needle site, the healthcare professional inserts the needle into the artery, collects the blood sample, and applies appropriate pressure and dressing.
Parameters Measured in Arterial Blood Gas
- Partial pressure of oxygen: Reflects the amount of oxygen dissolved in the blood and its movement from the lungs to the bloodstream.
- Partial pressure of carbon dioxide: Indicates the level of carbon dioxide dissolved in the blood and its elimination from the body.
- Blood pH: Measures the concentration of hydrogen ions in the blood, typically ranging from 7.35 to 7.45.
- Bicarbonate: Evaluates the chemical that helps maintain the blood’s pH within the normal range.
- Oxygen content and saturation: Measures the amount of oxygen in the blood and the percentage of hemoglobin carrying oxygen in red blood cells.
Risks and Precautions
- The risks associated with ABG testing are minimal, including possible bruising or a small wound at the site.
- Applying pressure at the puncture site helps reduce the chance of bruising.
- Some individuals may experience dizziness, faintness, lightheadedness, or nausea during the blood collection process.
- Although rare, there is a small risk of nerve or artery damage, leading to blockage in the artery.
- It is advised to avoid lifting or carrying heavy objects for approximately 24 hours after a blood draw from an artery.