O2 Delivery and Extraction Flashcards
How do you calculate the DO2?
CO x CaO2
How do you calculate CO?
HRT x SV
SV is dependent on?
Preload
Contractility
After load
How do you calculate the cardiac Index (CI)?
CO x body surface area
What does the ejection fraction reflect?
Contractility (volume of blood for each squeeze).
What does the preload reflect?
The heart stretch prior to contraction.
Preload occurs at what stage of the BP?
End diastole.
What does after load represent?
The force that resists contractions.
What does the ejection fraction reflect?
Contractility
Define contractility?
The ability of the heart to contract and eject blood into right ventricle and vasculature.
What calculation is this?
(Hb x 1.36 x SaO2) + (PaO2 x 0.003)?
Arterial O2 concentration.
What is CaO2?
Arterial O2 content
What is SaO2?
Arterial saturation of O2 and Hb.
What is PaO2?
Partial pressure of O2 in blood.
How do you calculate the oxygen extraction ratio (OER).
VO2/ DO2
What is the O2ER in the brain?
0.6
What is the O2ER in normal tissue?
0.3
When DO2 fails to meet VO2, this is known as?
Critical O2 delivery.
Which does not contribute to DO2?
BP or CO
BP
What type of hypoxia has a decreased DO2 from a decreased CaO2 secondary to Hypoxaemia from decreased PaO2 and SaO2.
Hypoxemic hypoxia.
With Hypemic hypoxia, what is decreased that leads to a decrease in CaO2, thus decreased DO2?
Hb
What is Haemoglobinopathy?
What time of hypoxia is it?
Effects the function of Hb.
Hypemic hypoxia
What happens to Hb with methemoglobinemia?
What type of hypoxia is it?
Hb normal, Dysfunctional Hb.
Hypaemic hypoxia.
What type of hypoxia is also termed circulatory shock?
Stagnant hypoxia.
Low CO
Low blood flow
Low DO2
