In a patient with no complaints and a PaCO2 of 30, what type of blood sample is described for measurement?

In a patient with no complaints and a PaCO2 of 30, what type of blood sample is described for measurement?

• A. Arterial sample
• B. Venous sample
• C. Capillary sample
• D. Mixed venous sample

Answer: (B)

PaCO2 is the partial pressure of carbon dioxide in arterial blood and is obtained from an arterial blood gas. To reflect gas exchange in the lungs accurately, the sample must come from an artery; venous blood carries CO2 that has been picked up from tissues and its CO2 level (PvCO2) does not equal the arterial PaCO2. Capillary samples can be used when arterial access isn’t feasible, but the standard measurement labeled PaCO2 refers to arterial blood. Mixed venous samples measure venous CO2 and are used for different assessments. So the described measurement corresponds to an arterial blood sample.

PaCO2 is the partial pressure of carbon dioxide in arterial blood and is obtained from an arterial blood gas. To reflect gas exchange in the lungs accurately, the sample must come from an artery; venous blood carries CO2 that has been picked up from tissues and its CO2 level (PvCO2) does not equal the arterial PaCO2. Capillary samples can be used when arterial access isn’t feasible, but the standard measurement labeled PaCO2 refers to arterial blood. Mixed venous samples measure venous CO2 and are used for different assessments. So the described measurement corresponds to an arterial blood sample.