Summary NUR 1400 ABG Interpretation Guide

3 Step ABG Interpretation
Mike’s Marching Band Suit Method


Marching band suit method

A B
pH 7.35 7.45 TEST TIP
B A
PaCO₂
35 45
Write this chart out 5 - 10 times every day the week
A B of your ABG exam.
HCO₃
22 26




Side Note: Many students & instructors use the ROME or Tic-Tac-Toe method, but that can get very confusing when interpreting
partial vs. full compensation. Use the marching band suit method to make it simple & get all your ABG questions
correct!


Set Up the Chart

Phase 1 - Set up the chart
pH is on 1st!
Step 1 Think pH is primary since it comes first.
pH CO2 comes 2nd.
Step 2 Look at the 2 in CO2, it comes 2nd.
PaCO₂ Lungs on top

HCO3 comes 3rd.
HCO₃ Step 3 Look at the 3 in HCO2, it comes 3nd.
Kidneys on bottom



Phase 2 - Key numbers to memorize

A B
pH 7.35 7.45

B A
Top line 7.35 - 7.45
PaCO₂ Middle 35 - 45 (7 goes to heaven)
35 45
Bottom 22 - 26 (think 2+2+2 = 6)
A B
HCO₃
22 26




Phase 3 - Label it A & B

A B

A cid pH 7.35

B
7.45

A
PaCO₂
35 45



B ase HCO₃
A

22
B

26

, 3 Step ABG Interpretation
Mike’s Marching Band Suit Method


How to Solve ABG Questions in 3 Steps
A B
pH
Step 1 - pH
pH 7.35

B
7.45

A
PaCO₂
pH is primary, look here first
pH below 7.35 = Acidosis
Primary 35
A
45
B
HCO₃
22 26
pH over 7.45 = Base (Alkalosis)



Step 2 - Match pH with partner
A B

pH
Example:
! ! 7.35 7.45


Let’s say pH is under 7.35, PaCO2 is B
A
Acidosis PaCO₂
35 45
over 45 & HCO3 is normal 2 acids match:
pH & CO2 = Respiratory Acidosis
! A Normal B
HCO₃
22 26
(look at the organ icon to help you)



Step 3 - Compensated or Uncompensated
Fully Compensated
MEMORY TRICK
A Normal B
Compensation means finding common pH
7.35 7.43 7.45
ground to make the pH within normal range.
B
A
PaCO₂
35 45
Fully Compensated = pH is within normal range A B
HCO₃
The lungs & kidneys are doing their part to 22 26

balance the body



Step 3 - Compensated or Uncompensated
Uncompensated

Memory Trick A B

Uncompensated = pH is OUTSIDE normal range pH
7.35 7.45


The “broken home”. The body is NOT TRYING to UNcompensated is very PaCO₂
B
A

help balance the pH. UNfriendly 35
A Normal
45
B
It’s like having a lazy partner in a relationship! HCO₃
22 25 26




Step 3 - Compensated or Uncompensated
Partially compensated
A B


Partially compensated = pH is OUTSIDE normal range, pH 7.35 7.45
but the body is trying! B A
PaCO₂
It is like couples counseling, sure the pH is NOT normal, 35 45
but at least the lungs & kidneys are TRYING to work things A
B
A
out. HCO₃
22 26 42