Hypoxia

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Hypoxia
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?????? ?????????????????????
Oxygen content of the arterial blood is lower
than normal that is called hypoxemia.
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Hypoxia
????????????? (Parameters of blood
oxygen)
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????? PaO2 13.3kPa(100mmHg)PvO2
5.32kPa(40mmHg)?
?????? ?????pO2????????????????
???? PaO2????????????(O2?Hb??)??????? ??????
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Hypoxia
???(CO2max) ???? ?PO2?19.95kPa(150mmHg)?PCO2?40m
mHg?38????, 100ml???Hb??????????
????? CO2max 8.92mmol/L (1.34ml/g15gHb
20ml)?
?????? Hb??(Hb??????)??
???? ??????????????(Oxygen-carrying capacity)?

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Hypoxia
???( CO2 ) ???? ?100ml???????O2???????
????? CaO2?8.47mmol/L(19.3ml)CvO2?5.35mmol/L(1
4ml)?
?????? PaO2 CO2max?
???? ???????????
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Hypoxia
?-????(A-VdO2) ???? ???????????????????
????? A-VdO2???2. 233.57mmol/L(5ml8ml)?
???? ??????????????????????????
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????? SaO29398
SvO27075?
?????? PaO2?
???? ??Hb????????
Factors affecting oxygen dissociation curve
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Hypoxia
P50 ?Definiens? One measure
of the position of the curve is the PO2 at the
50 SO2.
?Normal value? 3.473.6 kPa
(2627mmHg)?
?Influence? H?CO2 ????2?3-DPG
P50
?Significance? The P50 indicates
affinity of hemoglobin for oxygen.
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Etiology of hypoxia
2.??(Causes) ?????PO2?? ????????
????????? ????????????? PaO2??
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Etiology of hypoxia
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Etiology of hypoxia
?
?? ? ??
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?CO?Hb?????O2?210?,?????????0.1CO
?,???????????50??HbCO?
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???Hb????2050?,??????,????????????????????????
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Etiology of hypoxia
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Etiology of hypoxia
3.????????? Colour Change of skin and mucous
membranes
(1)????(Anemia) ???????????? (2)CO??(Carbon
monoxide poisoning) HbCO?????????(????)??
????HHb??????????? ??????????????
(3)??Hb(Methemoglobinemia) ??Hb???????,????Hb???,
?????(??)??????????? ?????
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Etiology of hypoxia
(?)?????(Circulatory hypoxia)
1.??(Feature) ????????????????,????????
???????????????
?Classification? ?
?????(Ischemic hypoxia) ?
?????(Congestive hypoxia)
2.??(Causes) ?????????(Generalize
d circulatory deficiency )
?????????(Local circulatory deficiency )
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Etiology of hypoxia
3.??????? (Characteristics of blood
oxygen) (1) ???????? (2) ???????? ? cO2max?? ?
paO2??caO2??SaO2??? ? pvO2??cvO2??SvO2? ? A-V
dO2??????
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3.??????? (Characteristics of blood oxygen) ?
CaO2max ?? ? PaO2?CaO2?SaO2?? ?
PvO2?CvO2?SvO2?? ? A - V??????????
4. ????????? ?????
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Etiology of hypoxia
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???????
?????????????? ???????????????????
?? ??????????????????????
(?)???????(Changes of respiratory system)
1. ?????(Increased rate depth of
ventilation) ????????????????
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?????? ????????(??????15)
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??????????????????,????????????
??,???????????
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???????
(3)????? ?????????KCa?KATP????? (4)??????
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???????
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???????
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???????
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???????
(?)CNS???( Dysfunction of CNS)
?????2,????????15,?????????23
????????5?,?????5-8min??????????
???????????,?????????????? ?????????????????????
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???????
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???????
(3)?????
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??? 1.???????????? 2.CO????????? 3.???????????????
??? 4.??????????????? 5.???????????????
?????????? ?????? 6.????????????????????? 7.
????????????????????????
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