1. The Department of Pathophysiology Guo lirong
Hypoxia
The Department of Pathophysiology
Guo lirong

2. Definition of hypoxia (What is hypoxia?) Parameters of Blood Oxygen
Main points to study
Definition of hypoxia (What is hypoxia?)
Parameters of Blood Oxygen

3. External respiration Tissue cells Blood Circulation Oxygen Supply
Hypoxia
External
respiration
Tissue
cells
Blood
Circulation
Oxygen
Supply
Oxygen
Utilization

4. Hypoxia
Definition
Hypoxia is the commonest pathological process，which is defined as that cells can not obtain enough oxygen or can not fully utilize oxygen，thus leading to changes in their metabolism，function，or structure.

5. Parameters of Blood Oxygen
Hypoxia
Parameters of Blood Oxygen
1.Partial pressure of oxygen（PO2）
2.Oxygen binding capacity（CO2 max）
3.Oxygen content（CO2 ）
4.Oxygen saturation（ SO2 ）

6. Partial pressure of oxygen（PO2）
Hypoxia
Partial pressure of oxygen（PO2）
1.Definition：the tension produced by oxygen molecules physically dissolved in plasma.
2.Normal value： PaO2=13.3kPa(100mmHg)
PvO2=5.33kPa(40mmHg)

7. Oxygen binding capacity （CO2max）
Hypoxia
Oxygen binding capacity （CO2max）
1. Definition：It is the maximum amount of oxygen that can be combined to hemoglobin in 100 ml of blood.
2.Normal value： 20ml/dl

8. Hypoxia
Oxygen content（CO2）
1.Definition：It is the actual content of oxygen in 100ml blood.
2.Normal value： CaO2=19ml/dl
CvO2=14ml/dl

9. Arteriovenous oxygen content (Ca-vO2)
Definition: It is the difference of oxygen content between arterial blood and mixed venous blood.
Normal value： 5ml/dl
19ml/dl
14ml/dl
5ml/dl O2 A V

10. = Oxygen saturation (SO2)
Hypoxia
Oxygen saturation (SO2)
Definition: It is the percentage of hemoglobin present as oxyhemoglobin.
CO2-dissolved O2
CO2max
100% =
SO2
Normal value：SaO2=95%; SvO2=70%

11. P50
Definition: P50 is a parameter reflecting the affinity of Hb to oxygen; it is the O2 pressure required to sturate 50% of Hb.
Normal value：26~28 mmHg

12. Dissociation curve of oxyhemoglobin
Hypoxia
Leftward-shifted curve: 20 40 60 80
100
Hb Saturation (%)
Rightward-shifted curve
pH↓
2,3-DPG↑
CO2 ↑
Temperature↑
PaO2 (mmHg)

13. Thank you