List 5 causes of a mixed venous oxygen saturation (SvO2) recording of 86%
Left to right shunt
Measurement error (poor calibration)
Reduced oxygen consumption – Hypothermia, NM blockade, hypothyroidism, general anaesthesia
One can usually group these "data interpretation" answers into a series of subcategories:
- bubble of gas in the sample
- poorly calibrated ABG machine
- Left to right shunt
- Microvascular shunt (eg. in sepsis)
- Hyperbaric oxygen therapy
- High FiO2
- Hyperdynamic circulation, eg. phaeochromocytoma or ECMO
- Neuromuscular blockade
- Deep sedation / anaesthesia
- Failure of mitochondrial oxygen use (eg. cyanide poisoning, sepsis)
A general overview of mixed and central venous saturation can be found elsewhere.
There is also an excellent article with satisfying explanations of the physiology behind oxygen delivery and extraction.
Walley, Keith R. "Use of central venous oxygen saturation to guide therapy."American journal of respiratory and critical care medicine 184.5 (2011): 514-520.