Acid Base II

Algorithm Metabolic Disorders

Met acidosis

Algorithm Respiratory disorders

  1. Look at pH
  1. Look at CO2
  1. Ask, Is there another problem?
  • 3a. Check Anion Gap

Hi: respiratory acidosis

Low: Respiratory alkalosis

3b. Is this Acute/Chronic?

3c. Is Bicarb appropriate?

  • With the Dime changes accounted for, is the expected = given (measured)

Dime change CO2, every 10 CO2, pH changes by

  • 0.08 if acute.
  • 0.04 if chronic.

Dime change CO2, every 10 CO2, pH changes by

  • 0.08 if acute.
  • 0.04 if chronic.

Dime Change, every 10 CO2

  • 1 Bicarb if acute
  • 3 Bicarb if chronic

Dime Change, every 10 CO2

  • 2 Bicarb if acute
  • 4 Bicarb if chronic

✏

  • too much bicarb, Met Alk
  • too little bicarb, Met Acid
  1. Look at pH: Low
  1. Look at CO2: also Low
  1. Are there other problems?

3a. Check Anion Gap: normal is 12 on shelf/step2

  • real life: Albumin x 3 = normal anion gap

⚠3b. Is PCO2 appropriate?

3c. In setting of Metabolic Acidosis, is there another Bicarb abrnomality?

Winters Formula: 1.5 Bicarb + 8

Measured > Expected

Respiratory Acidosis

Measured < Expected

Respiratory Alkalosis

Delta Delta? ehhh, too hard

Add Back

Screen Shot 2019-07-01 at 10.27.40 AM

✏ Normal Gap = 12, so if Gap is 30, there is 18 hydrogen ions.

  • These 18 H correspond to 18 Bicarb
  • add 18 Bicarb to the measured Bicarb to find out our starting Bicarb (e.g. 28)

Bicarb Normal = 24

Too much Bicarb (from V large Anion Gap)

Anion Gap Acidosis with Metabolic Alkalosis

Too little Bicarb (<24)

Anion Gap Acidosis w/ a NonGap Metabolic Acidosis

Met Alkalosis (easier)

  1. check pH: Hi
  1. Check CO2: high

⛔ Stop

  • Metabolic Alkalosis is Hyperaldosterone state

✏ Dustyn's Advice: This is Hard. If you don't master it, just take the hit on the shelf/step2. Its rare enough that you shouldn't waste time on a problem you will probably get wrong anyway

How to perform:

  • calculated Gap - 12
    • Add this to measured Bicarb
    • is it higher or lower than 24? Too high (combined met alkalosis), and vice versa