Review of Blood Gas Interpretation

Question 1

What are the 2 buffer systems in ABG’s?

Answer 1

Renal System
Respiratory System

Question 2

CO2 (PaCO2) =

Answer 2

= acid
In body fluid CO2 turns into carbonic acid

Question 3

More PaCO2 then more…..

Answer 3

Acid >45

Question 4

Less PaCO2 then more….

Answer 4

Alkaline < or closer to 35

Question 5

Bicarbonate (HCO3) =

Answer 5

Base
In body is alkaline substitute

Question 6

More HCO3 more….

Less HCO3 more…..

Answer 6

Alkaline

Acid

Question 7

CO2 is controlled by…..

Answer 7

Lungs 🫁 = respiratory

HCO3 is controlled by kidneys = metabolic

Question 8

Blood gas value pH

Answer 8

7.35-7.45

Question 9

pCO2 =

Answer 9

35-45 mm Hg

Question 10

HCO3 =

Answer 10

22-26 mEq/L

Question 11

pO2=

Answer 11

80-100 mm Hg

Question 12

SaO2 =

Answer 12

> 95%

Question 13

Blood gas interpretation
Consider pH (7.35-7.45)
Label as acid…..
Label as Alkaline

Answer 13

Label as acid <7.35
Label as Alkaline >7.45

If pH is normal and CO2 or HCO3 is not, label as “acid” or “alkaline” based on which side of 7.40 falls

Which matches the pH “Who’s your daddy”

Consider PaCO2 (35-45)
Label as acid (>45) or alkaline (<35)

Consider HCO3 (22-26)
Label as acid (<22) or alkaline (>26)

Question 14

Low Acidemia

Answer 14

pH
\
Low
|
Acidemia
/ \
High PCO2 Low HCO3
\ /
Resp. Metabolic
Acidosis Acidosis

Question 15

High Alkalemia

Answer 15

pH
\
High
|
Alkalemia
/ \
Low PCO2 High HCO3
\ /
Resp. Metabolic
Alkalosis Alkalosis

Question 16

Determine if it’s compensated or uncompensated

Answer 16

After identifying whether the blood gas is Acidosis or Alkalosis and whether it’s a Respiratory or Metabolic issue, we must now observe the compensatory component of the ABG results

Question 17

When There is a respiratory problem PaCO2 our body will compensate with?

Answer 17

Bicarbonate

Question 18

When there is a metabolic problem HCO3-, our body will compensate with?

Answer 18

Carbon dioxide

Question 19

Metabolic compensation:
When we have respiratory acidosis the body will try to compensate by increasing the amount of?

Answer 19

Bicarb in our system

Question 20

HCO3 Bicarbonate is a “blank”so one of its functions is to neutralize the “blank” that is causing the problem

Answer 20

Base

Acid

Question 21

When we have respiratory alkalosis it will do the opposite by?

Answer 21

Decreasing the amount of bicarb

Question 22

To conclude that there is compensation, the increase or decrease in HCO3 minus by carbonate hast to go outside the normal range. In other words it has to be lower than 22 or higher than 26, if the bicarbonate value is still within normal limits, you can conclude that?

Answer 22

There is no compensation

Question 23

We need to look at the bicarb to determine if it’s?

Answer 23

Compensated or uncompensated

Question 24

Compensated or uncompensated?

Answer 24

ph 7.30 low
pCO2 58 High
HCO3 24 is normal
p02 is 89 Low
This is respiratory acidosis

Since the bicarb value HCO3- is 58 the body detected acidosis so the body try to compensate by increasing the amount of base in the system. This tells us that there is definitely some compensation going on.

Is this a full compensation or partial compensation? To answer this question we need to look back at the pH since the pH of 7.30 is outside of the normal range this means that the compensation was not enough to bring the pH back to normal interpretation partially compensated respiratory acidosis. Remember a partial compensation only occurs in an abnormal pH because the compensation is not enough to bring the page back to normal. For there to be full compensation, the pH would need to be within the normal range.