Question

An anesthesiologist asked you to obtain mixed venous blood for the calibration of SVO2 value (in vivo calibration). From which of the following lines should you obtain the blood sample?

A) Arterial line
B) Peripheral IV
C) Side port of introducer placed in the internal jugular vein
D) Proximal (blue) port of the PAC
E) Distal (yellow) port of the PAC

Answer 1

To calibrate SVO2 values, mixed venous blood should be collected from the distal (yellow) port of the Pulmonary Artery Catheter (PAC). This site provides accurate representation of systemic venous return used for calibration by the anesthesiologist.

Step-by-step explanation:

The mixed venous blood for calibrating SVO2 values by an anesthesiologist should be obtained from the distal (yellow) port of the Pulmonary Artery Catheter (PAC), also known as the Swan-Ganz catheter. This catheter measures various aspects of heart function, and its distal port, located in the pulmonary artery, provides access to the mixed venous blood reflecting the systemic venous blood return from the entire body.

Blood in the pulmonary artery is deoxygenated, making it the correct location to obtain mixed venous blood. The right atrium is where all the systemic venous return collects, flowing from either the superior or inferior vena cava. The distal port of the PAC, being lodged within the pulmonary artery, is in the pathway of this venous return and therefore an ideal site for sampling the mixed venous blood needed by the anesthesiologist.