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#1
12-13-2012
 USMLE Forums Guru Steps History: 1+CK+CS Posts: 387 Threads: 82 Thanked 612 Times in 234 Posts Reputation: 622
A Stepwise Approach for Acid‐base and Acute Metabolic Disorders

A Stepwise Approach for any Acid-base problems in the step 2 ck exam

1 ‐ What is the likely clinical diagnosis (based on history)
*ASA overdose – mixed
*Vomiting – alkalosis
*COPD with sepsis – mixed resp and met acidosis
*COPD with sepsis and vomiting – triple acid base – resp acidosis, gap acidosis and metabolic alkalosis
*COPD with sepsis and diarrhea – triple acid base – respiratory acidosis, gap and non‐gap metabolic acidosis
2 ‐ Alkalosis or acidosis
*< 7.40 primary disorder = acidosis
*> 7.40 primary disorder = alkalosis
3 ‐ Calculate the anion Gap
*Anion gap = Na – HCO3 – Cl
*Normal gap is 12 +/‐ 2 (10 to 14)
4 ‐ Calculate the Delta gap (To verify if a there is a “hidden” coexistent)
*Delta gap = anion gap – 12 (the calculated anion gap – normal anion gap)
*Compared to normal range
> Normal (24) → metabolic alkalosis
< Normal (24) → hyperchloremic acidosis
5- Calculate and starting HCO3
* starting HCO3= Delta gap + current HCO3
If starting HCO3 < 24 = a coexistent non‐gap metabolic acidosis is present
If starting HCO3 > 24 = a coexistent metabolic alkalosis is present
6‐ check for respiratory compensation
7 ‐ Is it simple or mixed acid‐base disorder
8 ‐ Make clinical correlation and final diagnosis

Plz refer to
ALL Possible Acid-base problems
 The above post was thanked by: abbas.rz (10-01-2014), aknz (12-13-2012), anomali (12-13-2012), drsofiashamim (12-13-2012), fadi551 (12-15-2012), fyzah (12-13-2012), Mohammed Hassan (03-24-2013), Novobiocin (12-13-2012), rigbbm (07-03-2013), the_emperor (12-14-2012), Valkyrie (12-14-2012)

#2
12-13-2012
 USMLE Forums Newbie Steps History: Not yet Posts: 1 Threads: 0 Thanked 0 Times in 0 Posts Reputation: 10
more reading required prior doing this

wer can i read more. this was too precise. im really bad with this calculations.do u have any links wer i can learn it in broader way
#3
12-14-2012
 USMLE Forums Scout Steps History: CK Only Posts: 23 Threads: 1 Thanked 48 Times in 15 Posts Reputation: 58

Quote:
 Originally Posted by heartbeat A Stepwise Approach for any Acid-base problems in the step 2 ck exam 1 ‐ What is the likely clinical diagnosis (based on history) *ASA overdose  mixed *Vomiting  alkalosis *COPD with sepsis  mixed resp and met acidosis *COPD with sepsis and vomiting  triple acid base  resp acidosis, gap acidosis and metabolic alkalosis *COPD with sepsis and diarrhea  triple acid base  respiratory acidosis, gap and non‐gap metabolic acidosis 2 ‐ Alkalosis or acidosis *< 7.40 primary disorder = acidosis *> 7.40 primary disorder = alkalosis 3 ‐ Calculate the anion Gap *Anion gap = Na  HCO3  Cl *Normal gap is 12 +/‐ 2 (10 to 14) 4 ‐ Calculate the Delta gap (To verify if a there is a hidden coexistent) *Delta gap = anion gap  12 (the calculated anion gap  normal anion gap) *Compared to normal range ‐ > Normal (24) → metabolic alkalosis ‐ < Normal (24) → hyperchloremic acidosis 5- Calculate and starting HCO3 * starting HCO3= Delta gap + current HCO3  If starting HCO3 < 24 = a coexistent non‐gap metabolic acidosis is present  If starting HCO3 > 24 = a coexistent metabolic alkalosis is present 6‐ check for respiratory compensation 7 ‐ Is it simple or mixed acid‐base disorder 8 ‐ Make clinical correlation and final diagnosis Plz refer to ALL Possible Acid-base problems
don't forget the winter formula which is used in cases of metabolic acidosis to see if its compensated or combined with respiratory acidosis :
WF= HCO3*1.5+8
it should give u compensated value of CO2
if its more than expected then its combined acidosis
this is helpful in any case of M. acidosis
 The above post was thanked by: fadi551 (12-15-2012), heartbeat (12-15-2012), Mohammed Hassan (03-24-2013)
#4
12-15-2012
 USMLE Forums Guru Steps History: 1+CK+CS Posts: 387 Threads: 82 Thanked 612 Times in 234 Posts Reputation: 622

Quote:
 Originally Posted by drsofiashamim wer can i read more. this was too precise. im really bad with this calculations.do u have any links wer i can learn it in broader way
For sure if you read this thread carefully and then practice Qs from bottom link you will be satisfied, if not you can use internet.

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