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# Acid Base

Approach

-   Acidemia vs Alkalemia
-   Calculate anion gap: Na - (HCO+Cl)
-   Calculate the change in Anion Gap: AG - 12
-   Calculate the delta delta: Change in Anion Gap + HCO3 should
    equal 24. If \< 22, concomitant NAGMA. If \> 26, concomitant Met Alk
-   Assess if compensation is adequate.

## Compensation

### Metabolic Acidosis PCO2 = last 2 digits of pH PCO2 =

1.5\*HCO3 + 8

### Metabolic Alkalosis PCO2 = 40 + .6 \* (HCO3-24) aka the change in

bicarbonate

### Respiratory Acidosis Acute: HCO3 = delta_PaCO2 / 10 OR pH change =

0.008 \* CO2 change. (38 normal in SLC)

Chronic: HCO3 = (delta_PaCO2 / 10) \* 3.5 or pH change = 0.003 \* CO2
Change

### Respiratory Alkalosis Acute: HCO3 = delta PaCO2 / 10

Chronic: HCO3 = (delta_PaCO2 / 10) \* 3.5

## Stewart Approach

Strong ion approach
-<https://journals.lww.com/ccmjournal/Abstract/2007/11000/Disorders_of_acid_base_balance.23.aspx>

" In Stewart’s paradigm, H+, OH-, HCO3-, and CO32- are relegated to the
status of dependent variables, i.e. they can only be formed from the
differential movements and exchanges of independent strong ions (Na+,
K+, Cl-) that disturb electroneutrality, which is immediately corrected
by the hydrolysis of water and reaction with carbon dioxide."

Base excess: = the amount of strong acid (complete dissociated from H+)
needed to restore 1L of blood to pH of 7.4 at 40 mmHg. Used to isolate
metabolic component from respiratory compensation.