Flashcards in Acid-Base Disorders Deck (24):

1

## emia vs osis

###
emia: pH change aWAY from the reference range

osis: abnormal condition or process that CONTRIBUTES to pH change

2

## Normal pH, pCO2, HCO3

###
7.4

40

24

3

## What are implications of the Henderson Hasselbach equation?

###
If pCO2 increases then pH decreases

If HCO3 increases then pH increases

4

## What are the steps to identify acid base disorders?

###
1. Henderson‐Hasselbalch equation

• to determine whether metabolic or respiratory process is the primary

process driving acidosis or alkalosis

2. Anion gap

• AG ≥ 20, metabolic acidosis is present

3. Expected pCO2 range

• Determines whether respiratory compensation is adequate, under‐,

or over‐compensation

4. Excess anion gap (ΔΔ)

• Used only if there is an anion gap

• Determines “corrected” bicarbonate to see whether there are any other metabolic disturbances

5

##
7.5

29

22

###
Alkalosis

CO2 LOW ---> Hyperventilation

HCO2 low normal

Primary respiratory alkalosis (acute)

6

##
7.34

60

31

###
Acidosis

CO2 HIGH --> Hypoventilation

HCO3 HIGH --> compensated/chronic?

Primary respiratory acidosis, chronic

7

##
7.20

21

8

###
Acidosis

CO2 LOW --> hyperventilation

HCO3 LOW --> Metabolic

Primary metabolic acidosis

8

## How do you calculate the AG?

### Na - Cl + HCO3

9

## What does hte gap represent?

### unmeasured anions (Phosphates, sulfates, albumin)

10

## What is the normal range for the AG?

### 7-16 (12)

11

## What is an AG acidosis?

### pH decreases and acidosis

12

## If AG is >20?

### metabolic acidosis is present regardless of pH or HCO3

13

##
Why do we calculate the expected pCO2 range?

### Determines whether respiratory compensation is adequate, under‐, or over‐compensation

14

## How do you calculate hte expected pCO2 range?

### Expected Range = 1.5 ×(measured HCO3‐) + 8 ±2

15

## If pCO2 = 28

### > the expected range, then respiratory acidosis even though pCO2 is below 40.

16

## If pCO2 20

### within the expected range, then normal respiratory compensation.

17

## Why do we calculate the excess AG?

###
ONLY if there is an AG

determines "corrected" bicarb to see whether there are other metabolic disturbances

18

## excess AG formula?

### calculated AG - 12

19

## Corrected HCO3

### measured HCO3 + exccessAG

20

## If corrected HCO3 > 30

### underlying primary metabolic alkalosis

21

## If corrected HCO3 <23

### underlying primary metabolic acidosis

22

##
pH 7.5

pCO2 20

Na 140

Cl 103

HCO3 15

###
ONE:

Alkalosis

pCO2 LOW --> hyperventilation

**PRIMARY respiratory alkalosis

AG?:

AG = 140 - (103 + 15) = 22 (greater than 12!)

**Underlying primary metabolic acidosis

pCO2 range?:

1.5 x 15 + 8 = 30.5 (Greater than 18-22!)... Since a pCO2 of 20 is BELOW the expected range then respiratory alkalosis

Excess AG?

22-12 = 10

Corrected = 15 + 10 = 25 No hidden acid/alkalosis

23

##
7.20

25

Po2 130

O2 sat 94%

###
1. Primary:

Acidosis

CO2 LOW

HCO3 10

* Primary metabolic acidosis

2. AG

AG = 130 - (80+10) = 40

> 20 *metabolic acidosis is present

3. PCO2 range

Expected pCO2 = 1.5 x 10) + 8 +/-2= 21 -25

* PCO2 falls w/in the range so there is normal resp compensation

4. Expected AG

40-12 =28

Corrected HCO3 = 10 +28 = 38

* Primary metabolic alkalosis

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