Factors affecting PvO2

Normal mixed venous oxygen tension (PvO₂) is approximately 40 mmHg, representing the balance between oxygen consumption and oxygen delivery. A true PvO₂ measurement must come from a mixed venous blood sample containing venous drainage from the SVC, IVC, and the heart. Thus, the sample should be obtained from a pulmonary artery catheter. There are several factors that determine PvO₂, which can be remembered using the mnemonic COALS:

1. Cardiac output
2. Oxygen consumption
3. Amount of hemoglobin
4. Loading of hemoglobin
5. Saturation of hemoglobin

Of note, PvO₂ can be used in lieu of SvO₂ (mixed venous oxygen saturation), which is normally 65-75%.

Subspecialty

Keyword history

See Also:

Sources

1. Butterworth IV, JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s Clinical Anesthesiology, 5th ed. New York, NY: McGraw Hill; 2013
2. Jensen, Niels (2003). Clinical Arterial Blood Gas Analysis. Retrieved from https://www.anesthesiologyboards.com/written/sample.html.

Defined by: Lindsay Regali, MD