Questions Corner

[ahmedfathalla]

Hey Guyz,

Please post your questions regarding toxicology here (as we did with community). We want all the questions in one basket...errr...post!!

Thanks, and study hard!!

[Google]

[dr_yoyo]

hi doctors,
i want last year exam  (DOR TANY)

[einstein]

please Dr Samar:

1-what are the indications of ABG as an investigation: changes in PO2 & PCO2 only or change in PH also?

2-in doing the ABG in case of CO poisoning, will we find both PO2 & PCO2 elevated?

3-in our toxicology book, it is mentioned that the toxicity of H2S is due to its binding & inhibition of cytochrome oxidase, just as for cyanide, so how come there is cyanosis of the skin in case of H2S & red color of the skin in case of CO?
NB.in the community book it is mentioned that the mechanism of toxicity of H2S is the CNS depression of Respiratory center, I do not know which mechnism is the right one?   

[princess_ami]

ok Enistien i found these thing for u :

when to consider ABG measurement ?

in these critical scenarios :
-any unexpected deteriration in an ill patient
- anyone with acute exacerbation of a chronic chest condition
- anyone with impaired consciousness
- anyone with impaired respiratory effort

or if any of these signs and symptoms are present :
bounding pulse , drowsy , tremors , headache, pink palms , papillodema ( sighns of CO2 retention )
cyanosis , confusion , visual hallucination ( signs of hypoxia )

it includes :
PH
PaCO2
PaO2
Base excess

that's enough for that

[drsamar]

ok einstein take care the red colour in CO is due to the carboxy hemoglobin formation. carboxy hb is red in colour and u tend to see that thru the skin. as for h2s no co is formed and the only problem is that cytochrom oxidase is not functioning and so there is no utilization of oxygen so ther is asphyxia histotoxic type and thus cyanosis

[einstein]

thx Dr Samar, but what i was thinking of is that both CO & H2S do not affect the level of oxyhemoglobin which is red in color so the skin may be red in both & hence i asked  if the PO2 in both does not change, am i right?

[drsamar]

co replaces the oxygen in the oxyhemoglobin and transforms it into carboxyhemoglobin so how come wont it affect the oxy hb?

[drkimo]

co replaces the oxygen in the oxyhemoglobin and transforms it into carboxyhemoglobin so how come wont it affect the oxy hb?

i heard too,tht the O2 which couldnt bind wth Hb in case of CO poisoning dissolves in the plasma  So, the PaO2 is not changed. but the oxyHb decreases...
 So NO changes in the ABG

Is that Right??

[drsamar]

true kimo and i am glad u are nobody

[I-queless]

what does the renal test "BUN" stand for?
also the liver function tests "SGOT" and "SGPT"?

[ahmedfathalla]

i think that the "U" is for urea and "N" for nitrogen

[drkimo]

thnx Dr.
BUN>>blood,urea and nitrogen  >>renal function tests.

sGPT,sGOT>>liver enzymes elevated in the liver dysfunction(iron,paracetamol and zinc phosphide)

*all have liver toxicity
*all have stages in their C/P
*liver symptoms in stage III
*all need liver support(vitK,B,,salt free albumin,Glucose)

  grouping to most imp. drugs..

[I-queless]

thanks a lot

[einstein]

what about cyanide toxicity Dr Samar, why the skin is red in color?

[drsamar]

because cyanomethemoglobin is brick red in colour