all you budding internists....

[felipe5]

---

Members don't see this ad.

bust out your acid base expertise on this UW question I don't understand....

whats the disturbance here:
pH: 7.2
pCO2: 29
HCO3: 11
Na: 135
Cl: 102

So UW says the answer is met. acidosis + respiratory alkalosis, but wouldn't this be a met acidosis + resp acidosis? they use 1.5 (HCO3) + 8 as their winter's formula and say that 29 is close enough to 24.5 (their winter's result) and that indicates proper compensation. Am I missing something? i thought that you use winters to calculate a range (by using +/- 2) and if the actual co2 is higher than your range then you are have a resp acidosis with it too?!??!! apparently 75% of peeps get this and i'm just a *****. ayudame!

 

[tia99]

bust out your acid base expertise on this UW question I don't understand....

whats the disturbance here:
pH: 7.2
pCO2: 29
HCO3: 11
Na: 135
Cl: 102

So UW says the answer is met. acidosis + respiratory alkalosis, but wouldn't this be a met acidosis + resp acidosis? they use 1.5 (HCO3) + 8 as their winter's formula and say that 29 is close enough to 24.5 (their winter's result) and that indicates proper compensation. Am I missing something? i thought that you use winters to calculate a range (by using +/- 2) and if the actual co2 is higher than your range then you are have a resp acidosis with it too?!??!! apparently 75% of peeps get this and i'm just a *****. ayudame!

I am not a future internist, but i'll still give this a try. This is a metabolic acidosis with respiratory alkalosis (as the compensation). For these questions, i prefer to use logic as opposed to calculations/formulae.
One way to think about it is to figure out the primary disturbance (i.e. met acidosis) and then think about what you would expect the compensation to be (i.e. resp alkalosis). Also, when you see a pCO2 of 29, you shouldn't call it a resp acidosis (because in a resp acidosis, pCO2 should be high, not low).
This is my way of doing things. But you should use the method that makes the most sense to you. Even if you prefer to use calculations, use logic too, so that you have a way of checking to see if your calculations are correct.

 

[chrisisinnocent]

You cannot have respiratory acidosis with a pCO2 of 29.

 

[felipe5]

well not a primary resp acidosis, but if she had two disturbances together i thought the resp acidosis could manifest itself as an inadequate compensation to the metabolic acidosis. if that pt was losing CO2, just not enough though, i thought she could still have a resp acidosis with a low Co2 through winter's formula. i just thought this was one of those wacky acid base questions where you have to bust out winters formula and the delta-gap equations to see if there are multiple acid base disturbances. i've seen in questions where a pt can have a metabolic acidosis and metabolic alkalosis at the same time with a bicarb of 11 by doing the whole delta gap equation

anyways i'm over this ****, whateva

 

[JulianCrane]

Fleeps,
You're ahead of the game cuz you know of Winter's formula and the delta gap equation. 😉

well not a primary resp acidosis, but if she had two disturbances together i thought the resp acidosis could manifest itself as an inadequate compensation to the metabolic acidosis. if that pt was losing CO2, just not enough though, i thought she could still have a resp acidosis with a low Co2 through winter's formula. i just thought this was one of those wacky acid base questions where you have to bust out winters formula and the delta-gap equations to see if there are multiple acid base disturbances. i've seen in questions where a pt can have a metabolic acidosis and metabolic alkalosis at the same time with a bicarb of 11 by doing the whole delta gap equation

anyways i'm over this ****, whateva

 

[MSI-Scrub]

I am not a future internist, but i'll still give this a try. This is a metabolic acidosis with respiratory alkalosis (as the compensation). For these questions, i prefer to use logic as opposed to calculations/formulae.
One way to think about it is to figure out the primary disturbance (i.e. met acidosis) and then think about what you would expect the compensation to be (i.e. resp alkalosis). Also, when you see a pCO2 of 29, you shouldn't call it a resp acidosis (because in a resp acidosis, pCO2 should be high, not low).
This is my way of doing things. But you should use the method that makes the most sense to you. Even if you prefer to use calculations, use logic too, so that you have a way of checking to see if your calculations are correct.

I know it sounds good, but logic is not enough to answer an acid base question at times. As someone already stated, there may be compensation, but is it adequate? You need to punch some numbers to really really know

 

[normansatx]

I will give it a shot... but it may be a little off. I am a fourth year going into internal medicine.
Primary non anion gap metabolic acidosis with a partial compensation with respiratory alkalosis.
pCO2 is a little low indicating the person attempted to blow off extra acid as pCO2 to compensate, but didnt quite make it b/c winter's indicates it should be 24 +/- 2 and its only 29. In the case of a superimposed respiratory acidosis the pH would be a little lower and the pCO2 would be > 35 due to retention. (Clue.. if the bicarb and pco2 are going in opposite directions you most likely have a mixed picture)
Delta/delta is used to see if there is a non-anion gap met acidosis with the gap acidosis. The delta/delta in this case is about 1 (Gap is 12 and nml HCO3 - ptHCO3 is about 12) indicating there is only one process going on.
A stepwise approach is always best:
1. Whats the pH (alkalemia vs acidemia?)
2. look at pCO2 and bicarb
3. Calculate gap - if non AG met acidosis do a urine osmolar gap
4. Winter's formula ONLY IN MET ACIDOSIS
5. Possible dela/delta if bicarb is even lower than the pH would indicate