W2 Oxygen Delivery (Intro) - Bronwyn Avard

Question 1

Why is oxygen important in normal function of the human body?

Answer 1

Oxygen is essential for optimal cell function as much more ATP is produced when oxygen is present and energy is stored in the form of ATP and energy is required for cell function.

Question 2

Under aerobic conditions, how much ATP is produced by a cell?

Answer 2

While glycolysis will produce 2xATP (anaerobic), in aerobic conditions the subsequent citric acid cycle produces another 2xATP, the electron transport chain and oxidative phosphorylation will produce 34xATP

Question 3

What is the ideal alveolar gas equation?

Answer 3

{(760-47)xFiO2 }- (ppCO2/0.8)

The humidification of airways x the percentage of oxygen in the atmosphere, minus the dilution due to increased [CO2] in the lungs.

Question 4

What is necessary for transporting oxygen to cells?

Answer 4

1. patent airway
2. functioning lungs
3. adequate amount and type of haemoglobin.
4. good cardiac output
5. normal diffusion across capillary membrane and through tissues into cells.

Question 5

What is oxygen delivery?

Answer 5

Cardiac output X arterial oxygen content

Question 6

What is cardiac output?

Answer 6

stroke volume X heart rate

Question 7

What is stroke volume?

Answer 7

A combination of:

1. Preload - amount of blood that fills into the ventricle, i.e. amount of blood returning to the heart.
2. Afterload - the amount of tension to overcome i.e. greater dilation of ventricle has greater afterload.
3. Contractility

Question 8

How is arterial oxygen content calculated?

Answer 8

[Hb] x SaO2 x 1.30 (+PaO2 x 0.003)

1. Concentration of haemoglobin (g/L)
2. amount of oxygen carried by haemoglobin if saturated
3. % saturation
4. amount dissolved in plasma

Question 9

Define shock

Answer 9

inadequate oxygen delivery to the tissues to meet their metabolic demand.
results in inadequate energy production, cell dysfunction, tissue/organ and ultimately death.