W9 D3 - Mixed Venous Gases

Question 1

When are mixed venous gases used?

Answer 1

Unstable patients with a PA catheter:
* CV surgery
* Shock
* Sepsis
* ARDS
* Multi system organ failure

Question 2

What do mixed venous gases tell us?

Answer 2

1. Gives us information on oxygen supply and demand
2. Differentiate types of shock
3. Trend effectiveness of treatment

Question 3

How do we measure if O2 is getting into the cells?

Answer 3

Physical assessment
* skin colour
* temperature
* cap refill
* LOC
* vital signs

Lactate level ^^ anaerobic metabolism
* only 2 ATP produced (34-38 norm)
* lactic acid released so cells dont die

Mixed venous oxygen saturation
* only measures oxygen levels in cells

Question 4

Differentiate
PaO2

Answer 4

PaO2 - oxygen dissolved in arterial blood
SaO2 - oxygen bound to hemoglobin in arterial blood
VO2 - tissue oxygen demand
SvO2 - oxygen bound to hemoglobin in venous blood PA
ScvO2 - oxygen bound to hemoglobin in central venous blood