hypoxemia

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hypoxemia

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drpkaur
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08/18/06 - 04:28 PM

In which of the following diseases would you expect a low arterial PO2 and a low oxygen saturation (SaO2)?
A. CO poisoning
B. Fe++ def anemia
C. decreased CO
D.Respiratory Acidosis
E. Cyanide poisoning

ssrpk
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08/18/06 - 04:53 PM

D.Respiratory Acidosis

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plastic_girl
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08/19/06 - 12:04 AM

Why not A. CO poisoning???

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icemaiden
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08/19/06 - 01:04 AM

CO doesnt dissolve in plasma,so doesnt lower arterial pO2

nirvanamona
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08/20/06 - 03:27 PM

yeah and the only component CO and methHBemia changes is oxygen saturation, SaO2, otherwise PaO2 and O2 content remains unchanged.

with anemia, Hb concentration is low, SaO2 and PaO2 are normal

drpkaur
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08/22/06 - 05:18 PM

ssrpk could u plz explain ur point..

young_doc
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08/22/06 - 09:48 PM

D?

If you have a Resp Acidosis, it means 2 things:

-you're hypoventilating. Hence the cause of the low arterial pO2.

-you've just shifted your O2-saturation curve to the right (thanks to the acidity), hence decreasing O2 saturation (by decreasing Hb's affinity for O2)

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DrS
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08/22/06 - 11:30 PM

mytime
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08/23/06 - 07:54 AM

D...
in Co poisoning aterial pO2 sud not be low.In anemia saturation is not low.
Respiratory acidosis...both are low.in hypoventilation CO2 increases o2 decreases.PA-Pa gradient increases shunting takes place saturation is less.

drpkaur
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08/23/06 - 08:32 AM

#10

WELL SAID young_doc...thanx for ur nice explanation.answer is D....

If you have a Resp Acidosis, it means 2 things:

-you're hypoventilating. Hence the cause of the low arterial pO2.

-you've just shifted your O2-saturation curve to the right (thanks to the acidity), hence decreasing O2 saturation (by decreasing Hb's affinity for O2)

young_doc
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08/23/06 - 06:56 PM

#11

Just to add...pretty much the only things that affect blood O2 content are:

-Hb concentration

-Alveolar pO2

(So Carbon Monoxide, like Mytime said, we shouldn't get a decreases O2 content...only a decreases Saturation...likewise for cyanide)

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MRMAVERICK
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08/24/06 - 12:01 AM

#12

NICE DOC

Leopard
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09/03/06 - 03:36 PM

#13

young_doc wrote:
Just to add...pretty much the only things that affect blood O2 content are:

-Hb concentration

-Alveolar pO2

(So Carbon Monoxide, like Mytime said, we shouldn't get a decreases O2 content...only a decreases Saturation...likewise for cyanide)

In CO poisoning PaO2 remains normal but
1:SaO2 decreases
2:Total O2 content also decreases

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