DrVirgo
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What will pulse oximiter and ABG's show about SaO2 in Carbon Monoxide poisoning and why?
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| doc179
Forum Guru
Topics: 67
Posts: 1,217
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in CO poisoning the pulse oxymeter will show normal saturation as it just measures that the heamoglobin is occupied it does not say who is occupying those free places on the heamoglobin. partial pressure of O2,heamoglobin concentration will be normal...but O2 saturation will be decreased as CO is sitting on the heamoglobin instead of O2
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| dr_sarim
Forum Senior
Topics: 16
Posts: 75
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ABG's....pao2 =normal,paco2 i=normal or slightly decreased (well ,keeping it as simple as possible ....co has nothing to do with partial pressures )
pulse oximetry = sao2 decreased (because co displaces o2 from hemoglobin due to is higher affinity ,thus a decrease in oxygen saturation)
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| dr_sarim
Forum Senior
Topics: 16
Posts: 75
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i apologise for my wrong interpretation of oximeter reading...doc 179 is absolutely right
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| DrVirgo
Forum Hero
Topics: 1096
Posts: 3,515
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Pulse Ox will show normal SaO2 - cherry red pigment masks the cyanosis
ABG will show normal SaO2 - because it determines it from PaO2
(actually in CO pois. the SaO2 is decreased! -so pulse oximeter and ABG's are NOT a good way to check for CO poisoning)
So how can we diagnose it definitively?
(just by signs: cherry red pigment, and headache?)
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| dr_sarim
Forum Senior
Topics: 16
Posts: 75
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well..diagnosis is difficult
physicians has to be alert when some one presents with flu like symptoms (plus syncopal episode ,dypnes bla bla bla) in winter season ....question about the occupation, use of heaters...and i have come to know that there is a devise known as co-oximeter that is reliable
the diagnosis is difficult ,no doubt about it...i doubt the boards going into such detail in step 1
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| docarchana
Forum Guru
Topics: 70
Posts: 515
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in CO poisoning, pulse oximeter and ABG show normal SaO2.
goodinfo.. thanku.
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| Leopard
Forum Guru
Topics: 30
Posts: 401
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In simple words
Pulsoximeter cannot differentiate between
- OxyHb
- CarboxyHb
- MetHb
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