need help with your account or subscription? click here to email us (or see the contact page)
join telegramNEW! discord
jump to exam page:
search for anything ⋅ score predictor (โ€œpredict me!โ€)

NBME 21 Answers

nbme21/Block 2/Question#9 (reveal difficulty score)
A 40-year-old man is brought to the emergency ...
Metabolic acidosis and respiratory acidosis ๐Ÿ” / ๐Ÿ“บ / ๐ŸŒณ / ๐Ÿ“–
tags:

 Login (or register) to see more


 +4  upvote downvote
submitted by โˆ—mcl(670)
get full access to all contentpick a username

When working on acid/base disorders, it helps to look systematically at the following: (1) pH (which sadly was not given in this problem), (2) figure out which problem is primary by looking at PaCO2 and bicarb, and (3) look for any compensation (which the question doesn't ask but still).

Here, we see that the CO2 is high on the ABG. This means that patient is hypoventilating since levels of CO2 are ventilation dependent, and also that patient has respiratory acidosis. Also, bicarb is low, which implies that it's being "soaked up" by metabolic acidosis.

get full access to all contentpick a username
privatejoker  I just look at these as "what makes the most sense" and this is is sufficient in nearly every scenario. Out of the given options, the only explanation that even lines up with the given numbers is the answer choice. +



 +4  upvote downvote
submitted by โˆ—usmle11a(102)
get full access to all contentpick a username

i did the

(Hco3-)x1.5 +8 +-2

it should CO2 that is wat higher than compensation indicating mixed

another way is the โ†‘ โ†“ way

get full access to all contentpick a username



 -6  upvote downvote
submitted by โˆ—dr.xx(176)
get full access to all contentpick a username

Henderson-Hasselbach Equation: pH = 6.1 + log(HCO3 / (0.03 * PaCO2)); so here, pH = 6.92 => Acute (uncompensated) primary respiratory acidosis, with metabolic acidosis

get full access to all contentpick a username
sbryant6  calculator can't do logs yo. +5
b1ackcoffee  wow, sherlock! +1



Must-See Comments from nbme21

nosancuck on Absorption atelectasis
assoplasty on Free T4
seagull on GM2
lnsetick on Apocrine
niboonsh on NMDA receptors are blocked by Mg2+ at the ...
drdoom on Deletion of a hydrophobic amino acid ...
hayayah on HCO3โˆ’ transported in the plasma
mcl on Aortic
notadoctor on Usual interstitial pneumonitis
madojo on Genital herpes
hungrybox on Obstruction of the bile duct
jambo2222 on Lung
hungrybox on Mismatch repair
hungrybox on Hydrochlorothiazide

search for anything NEW!