HypoxiaPathophysiology departmentShiHeZi Medical College
Hypoxia Pathophysiology department ShiHeZi Medical College
ConceptTissue cells can'tobtain enough oxygenorcan'tfully utilize oxygenmetabolic, functional and structural changesOxgen supply=CaO,xQOxygenconsumption=（CaO,-CvO,)×Q
Concept Oxgen supply = CaO2× Q Oxygen consumption =（CaO2－CvO2）× Q Tissue cells can’t obtain enough oxygen or can’t fully utilize oxygen metabolic, functional and structural changes
Parameters ofbloodgasPartial pressureofO,(PO,)PaO,100mmHg,PvO240mmHgO,content（CO,)=CO,maxX SO,+dissolved O,Ca0,19ml/dl，Cv0,14ml/dlO,capacity（CO,max）=1.34m/g×Hbg/dlCO,- dissolved 02× 100%O2saturation（SO,）=CO,maxSv0270%Sa0,95%
CO2－dissolved O2 CO2max O2 saturation（SO2）= ×100% SaO2 95%, SvO2 70% Parameters of blood gas Partial pressure of O2（PO2） PaO2 100mmHg , PvO2 40 mmHg O2 content（CO2）= CO2max×SO2 + dissolved O2 CaO2 19ml/dl , CvO2 14ml/dl O2 capacity（CO2max）= 1.34 ml/g × Hb g/dl
100908o7060Suogeies502403020101o102030405060708090100P.Oz (mmHg)Dissociation curve of oxyhemoglobin
Dissociation curve of oxyhemoglobin
Total2210018O,combined80withHbo14Uogeinesq%601040Pso20DissolvedO80600601002040oPO(mmHg)
Classification,etiologyandpathogenesis1.Hypotonichypoxia—PaO2lCauses : 1) PiO212)pulmonary dysfunction3)shuntResults:PaO21SaO21→CaO21cyanosishypotonic hypoxemia,(PaO2-PMO,)-→（CaO2-CvO2)↓PaO, <60mmHg → VO21?
Classification, etiology and pathogenesis 1. Hypotonic hypoxia — PaO2↓ Causes : 1) PiO2↓ 2) pulmonary dysfunction 3) shunt Results : PaO2↓→ SaO2↓→ CaO2↓ hypotonic hypoxemia, cyanosis （PaO2－PMO2）↓ →（CaO2－CvO2）↓ PaO2 ＜ 60mmHg → VO2↓？
2.Hemic hypoxia-CO2max↓Causes: 1) anemia2)carboxyhemoglobinemia3)methemoglobinemiaenterogenous cyanosis4)Psol:transfusion ofdepotbloodResults:CO,max11 -CaO211→（CaO2-CvO,）P50 ↓→(CaO2-CvO,)
Results : CO2max↓↓ CaO2 ↓↓ （CaO2－CvO2）↓ P50 ↓ （CaO2－CvO2）↓ 2. Hemic hypoxia — CO2max ↓ Causes : 1) anemia 2) carboxyhemoglobinemia 3) methemoglobinemia enterogenous cyanosis 4) P50↓：transfusion of depot blood
3.Circulatory H-QCauses : general circulatory failurelocal circulatory disorderResult : Qll→ CvO2l→（CaO-CvO,)1
Result : Q↓↓→ CvO2↓ →（CaO2－CvO2）↑ Causes : general circulatory failure local circulatory disorder 3. Circulatory H — Q↓ ·
4.Histogenous hypoxiaCauses:1)histotoxicHcyanide poisoning2) cell injured by biological orphysical factor3) vitamin deficiency ---B,Result : CvO21→(CaO2 -CvO,)
4. Histogenous hypoxia Causes: 1) histotoxic H cyanide poisoning 2) cell injured by biological or physical factor 3) vitamin deficiency - B1 Result : CvO2↑ →（CaO2 － CvO2）↓
What kind of hypoxia might occur inseptic shock?
What kind of hypoxia might occur in septic shock ？