How is oxyhemoglobin saturation in arterial blood most commonly measured?

• A. Pulse oximetry
• B. Arterial blood gas analysis
• C. Capnography
• D. Venous blood gas analysis

Answer: (B)

Oxyhemoglobin saturation in arterial blood is most commonly measured using pulse oximetry. This non-invasive method utilizes light absorption characteristics of oxygenated and deoxygenated hemoglobin to provide estimates of arterial oxygen saturation. It is widely used in clinical settings due to its ease of use, rapid results, and ability to continuously monitor patients.

While arterial blood gas analysis does provide comprehensive information about oxygenation, including oxyhemoglobin saturation, it is an invasive procedure that requires drawing blood from an artery. Due to its complexity and the discomfort associated with the blood draw, it is not the primary method for routine monitoring of oxyhemoglobin saturation.

Capnography measures the concentration of carbon dioxide in exhaled air and is not used for assessing oxygen saturation. Venous blood gas analysis provides information about the gas exchange occurring in the venous system but does not accurately reflect arterial oxygen saturation levels.

Thus, pulse oximetry remains the preferred and most common method for measuring oxyhemoglobin saturation in arterial blood due to its convenience and efficiency.