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- Jan 25, 2007
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1. What do you all think is the extent that we need to know acid/base for Step 2 CK?
This is what I think based on the UWorld QBank questions:
-determine if primary metabolic/respiratory acidosis or alkalosis given labs or clinical picture
-calculate the anion gap if a metabolic acidosis, be able to interpret
-determine if there is adequate compensation for metabolic alkalosis/acidosis:
a) for metabolic alkalosis, using PaCO2 = (0.9xHCO3) + 16.
b) for metabolic acidosis, using PaCO2 = (1.5 x HCO3) + 8.
Anything else that we should know for purposes of Step 2?
2. I understand that with salicylates you get a mixed respiratory alkalosis and anion-gap metabolic acidosis. You can "suspect" this is ~normal pH with low HCO3, low PCO2 in the right clinical picture. On UW QID 2803, there are several answer choices which fit this picture of lab values, and from their explanation I do not fully understand how you get to the correct answer?
3. On UW, they indicate salicylate poisoning causes a resp alkalosis and AG metabolic acidosis concurrently. But I remember learning salicylates first cause a respiratory alkalosis (aspirin stimulates the respiratory center) then results in the AG metabolic acidosis. Upon researching, Up to Date has a similar statement [early respiratory alkalosis followed by the AG metabolic acidosis]. Is this simply a matter of time (usually see both occurring by the time the patient presents)?
This is what I think based on the UWorld QBank questions:
-determine if primary metabolic/respiratory acidosis or alkalosis given labs or clinical picture
-calculate the anion gap if a metabolic acidosis, be able to interpret
-determine if there is adequate compensation for metabolic alkalosis/acidosis:
a) for metabolic alkalosis, using PaCO2 = (0.9xHCO3) + 16.
b) for metabolic acidosis, using PaCO2 = (1.5 x HCO3) + 8.
Anything else that we should know for purposes of Step 2?
2. I understand that with salicylates you get a mixed respiratory alkalosis and anion-gap metabolic acidosis. You can "suspect" this is ~normal pH with low HCO3, low PCO2 in the right clinical picture. On UW QID 2803, there are several answer choices which fit this picture of lab values, and from their explanation I do not fully understand how you get to the correct answer?
3. On UW, they indicate salicylate poisoning causes a resp alkalosis and AG metabolic acidosis concurrently. But I remember learning salicylates first cause a respiratory alkalosis (aspirin stimulates the respiratory center) then results in the AG metabolic acidosis. Upon researching, Up to Date has a similar statement [early respiratory alkalosis followed by the AG metabolic acidosis]. Is this simply a matter of time (usually see both occurring by the time the patient presents)?
