Arterial Blood Gas

Question 1

Arterial Blood Gas (ABG)

Answer 1

• used to monitor your patient’s acid-base balance and to determine if they are compensating.
• done in artery only

Question 2

normal values:

pH

Answer 2

PH: 7.35 - 7.45

Question 3

Acidosis

Answer 3

• blood under 7.35, acidic
• respiratory acid
• high levels of PaCO2 in the blood leads to high acidity
• PaC02 controlled by respiratory system

Question 4

Alkalosis

Answer 4

• blood over 7.45, basic
• metabolic base
• High levels of HCO3 leads to highly basic
• PCO3 controlled by kidneys (metabolic)

Question 5

Normal Values:

CO2

Answer 5

PaCO2: 35-45 mmHg (respiratory determinant)

If PaCO2 is below 35 – alkalosis
If PaCO2 is above 45 – acidosis
If PaCO2 is 35 – 45 – normal ( always indicates a respiratory issues)

Question 6

Normal Values:

Pa02

Answer 6

PaO2: 75 – 100 mmHg

Question 7

Normal Values:

HCO3

Answer 7

HCO3: 22-26 mEq/L (metabolic determinant)

If HCO3 is below 22 – acidosis
If HCO3 is above 26 – alkalosis
If HCO3 is with in 22-26 – normal (always indicates a metabolic issue)

Question 8

Compensation

Answer 8

If the body is experiencing respiratory/metabolic the body should attempt to compensate by inducing the following condition

If respiratory acidosis (high CO2) then the body should induce metabolic alkalosis (release HCO3)

If metabolic alkalosis (high HCO3) then the body should induce respiratory acidosis (release CO2)

Question 9

Full compensation

Answer 9

PH is normal, PaCO2 and HCO3 are both oppositive and abnormal

Question 10

Partial compensation

Answer 10

PH is abnormal, PaCO2 and HCO3 are both oppositive and abnormal

Question 11

No compensation

Answer 11

PH is abnormal, PaCO2 and HCO3 are NOT both oppositive and abnormal

Question 12

Ex 1 ABG Results:
PH 7. 25
PCO2 65
HCO3 27

Answer 12

First thing
look at the PH (7.25) – is it within the normal range or is it below (acidic) or above (basic)?
The PH is 7.25 so it is acidic (we will place it in the acidic column)

Second
Look at the PCO2 – is it within the normal range or is it greater (acidic) or lower (Basic)
The PCO2 is 65 – we will put it in the acidic area as it is greater then 45

Third
Have a look at the HCO3 (Bicarb.)
Is it with in the normal range or is it higher then normal (base) or lower then normal (Acidic)
The HCO3 is 27 – it is higher so we will put it in the base

ANALYSIS
• PH is in the acidic spot so we know it is acidosis.
• IS it respiratory or metabolic acidosis?
• Since the CO2 is in the same column as PH – it is respiratory acidosis

COMPENSATION?
• We know it is respiratory acidosis but is their any compensation going on?
• With the HCO3 in the basic we say the the metabolic system is trying to balance (Partially Compensated Respiratory Acidosis)

Question 13

Ex 2 ABG Results:
PH 7. 65
PCO2 37
HCO3 36

Answer 13

First thing
look at the PH (7.65) – is it within the normal range or is it below (acidic) or above (basic)?
The PH is 7.65 so it is basic (we will place it in the basic column)

Second
Look at the PCO2 – is it within the normal range or is it greater (acidic) or lower (Basic)
The PCO2 is 37 – we will put it in the normal area

Third
Have a look at the HCO3 (Bicarb.)
Is it with in the normal range or is it higher then normal (base) or lower then normal (Acidic)
The HCO3 is 36 – it is higher so we will put it in the base

ANALYSIS
• PH is alkalosis - but is it metabolic or alkalosis?
• With the HCO3 in the same category it becomes metabolic alkalosis

COMPENSAITON
• The PCO2 is normal therefore it is Uncompensated Metaboic Alkalosis

Question 14

Ex 3 ABG Results:
PH 7. 36
PCO2 34
HCO3 19

Answer 14

There is no TIC TAC TOE here so we know there is some compensating but is it partial or full?

Here we have to look at what the PH is – we see that it is normal therefore we have full compensation

However, is it respiratory or metabolic?

With closer look at the PH we see that is closer to the acidic side. Now look at the other figures. The bicarb (HCO3) is also acidic, but the PCO2 is alkalotic (base). There fore we can say that the body is balancing the metabolic and respiratory system by decreasing the PCO2

With decreasing the PCO2 to make things more alkaline the PH will increase from its acidic state. Things are fully compensated.

If by chance the PH was not normal and the HCO3 was acidic, it would be partial compensation.
If the PH was not normal but the HCO3 was normal no compensation is happening.

So here we have metabolic acidosis the is fully compensated by respiratory alalosis