ABG READING/
ANALYSIS
What to Look for?
DEGREE OF COMPENSATION
• Uncompensated
• Partially Compensated pH VALUE
• Fully Compensated • Acidosis
• alkalosis
NATURE OF IMBALANCES
• RESPIRATORY
• METABOLIC
NORMAL VALUES
• pH
• 7.35 – 7. 45
• Partial Carbon Dioxide (PaCO2)
• 35 – 45 mmhg
• Bicarbonate(HCO3)
• 22 – 26 mmhg
ABG FULL NAME
FIRST NAME MIDDLE NAME LAST NAME
Represents the degree of Represents the nature of Represents the pH Value
compensation imbalance - Acidosis
- Partially Compensated - Respiratory - alkalosis
- Uncompensated - metabolic
- Fully compensated
1st step ( identify the last name by checking the pH
if acidosis or alkalosis)
pH
7. 35 – 7. 45
If < 7.35 = acidosis If > 7.45 = alkalosis
If in normal range, use
the rule of 7. 4
7. 40
Normally
From 7.35 – 7.39 = acidosis compensated
From 7. 41 - 7.45 = alkalosis
=
Balanced
Place an arrow as identifier : for GREATER THAN and FOR LESS THAN
Example1: You are called to see a 54 year old lady on the ward. She is three days post-cholecystectomy and
has been complaining of shortness of breath. Her ABG is as follows: pH: 7.49 , pCO2: 27 , HCO3: 22, Other
values within normal range.
1. Identify the pH value ( put an arrow
indicating the value)
• Ph is = alkalosis
• Write in the last name
FIRST NAME MIDDLE NAME LAST NAME
Represents the degree of Represents the nature of Represents the pH Value
compensation imbalance - Acidosis
- Partially Compensated - Respiratory - alkalosis
- Uncompensated - metabolic
- Fully compensated
Step 2: identify the middle name if
respiratory or metabolic)
2.1 identify first the value of carbon dioxide and bicarbonate
• PaCO2 • HCO3
• Normal values= 35 – 45 mmhg • Normal values = 22 – 26 mmhg
• If > 45 = acidosis • If > 26 = alkalosis
• If < 35 =alkalosis • If < 22 = acidosis
Less than greater than Less than greater than
alkalosis
acidosis
alkalosis
acidosis
PaCO2 HCO3
Plot arrows to your CO2 and CHO3 2.2 identify which one is the same
From the Example1: Her ABG is as follows: value with pH
pH: 7.49 = alkalosis
CO2 represents RESPIRATORY
pCO2: 27 = alkalosis
HCO3: 22 = normal
HCO3 represents METABOLIC
RESPIRATORY
ALKALOSIS
Another method: ROME method
This method is applied by
R - Respiratory looking at the arrows being
O - Opposite put at the values of pH,
CO2 and HCO3.
M - Metabolic
E - Equal
If the arrow from the PCO2 is opposite from the pH,
it is respiratory
If the arrow from the HCO3 is equal from the pH, it
is metabolic
Example1: You are called to see a 54 year old lady on the ward. She is three days post-cholecystectomy and has been
complaining of shortness of breath. Her ABG is as follows: pH: 7.49 , pCO2: 27 , HCO3: 22, Other values within normal
range.
2. Identify the middle name
pH: 7.49 = alkalosis
pCO2: 27 = alkalosis
HCO3: 22 = normal
alkalosis
FIRST NAME MIDDLE NAME LAST NAME
Represents the degree of Represents the nature of Represents the pH Value
compensation imbalance - Acidosis
- Compensated - Respiratory - alkalosis
- Uncompensated - metabolic
- Fully compensated
Step 3: Identify the First name
• If either PaCo2 or HCO3 is normal = uncompensated
• If all are not normal = partially compensated
• If pH is normal = Fully compensated
• If pH is exactly 7.4 = normally compensated
Example1: You are called to see a 54 year old lady on the ward. She is three days post-cholecystectomy and has been
complaining of shortness of breath. Her ABG is as follows: pH: 7.49 , pCO2: 27 , HCO3: 22, Other values within normal
range.
2. Identify the first name
pH: 7.49 = alkalosis
pCO2: 27 = alkalosis
HCO3: 22 = normal
uncompensated respiratory alkalosis
FIRST NAME MIDDLE NAME LAST NAME
Represents the degree of Represents the nature of Represents the pH Value
compensation imbalance - Acidosis
- Compensated - Respiratory - alkalosis
- Uncompensated - metabolic
- Fully compensated
LET’S EXERCISE!
•pH: 7.23, CO2: 48, HCO3: 24
•pH: 7.65, CO2: 48, HCO3: 31
•pH: 7.28, CO2: 52, HCO3: 22
pH: 7.42, CO2: 48, HCO3: 35
pH: 7.20, CO2: 53, HCO3: 28
