ABG's

Keith Martin, RN, BSN, BSc.

ABG's pH 7.35-7.45

• acid base balance is a reflection of the H+ ions PaCO2 35-45 mm Hg

• partial pressure of arterial carbon dioxide

• referred to as the respiratory acid PaHO3 22-26

• acid base component that reflects kidney function

• referred to as the metabolic base PaO2 80-100 mm Hg

• partial pressure of arterial oxygen dissolved in plasma BE ± 2

• total base excess o ↓ in BE = loss of base or metabolic acidosis o ↑ in BE = uptake of base or metabolic alkalosis

Sat > 95%

• percentage of hemoglobin bound to oxygen

Respiratory CO2 is the respiratory acid Too much = acidosis Too little = alkalosis

← 35 – 45 →

Metabolic HCO3 is the metabolic base Too much = alkalosis Too little = acidosis

← 22 – 26 →

Respiratory Acidosis

Respiratory Alkalosis

Metabolic Alkalosis Metabolic Acidosis

Who’s Your Daddy?

1st name

_____________________

Compensated or

Uncompensated

Middle Name (must match Daddy’s name)

_____________________

Respiratory or

Metabolic

Last Name

_____________________

Acidosis or

Alkalosis

Step #1: First Name

• Compensated or uncompensated

• If your pH is normal (between 7.35-7.45) then you are COMPENSATED

• If your pH is abnormal (<7.35 or >7.45) then you are UNCOMPENSATED Step #2: Last Name

• If your pH is less than 7.40, your last name is Acidosis

• If your pH is greater than 7.40, your name is Alkalosis e.g: pH 1st Name Last Name

7.36 ________________ ________________

7.20 ________________ ________________

7.59 ________________ ________________

7.38 ________________ ________________

Step #3: Who’s your Daddy

• Is you CO2 > 45 = respiratory acidosis or < 35 = respiratory alkalosis

• Is you HCO3 < 22 = metabolic acidosis or > 26 = metabolic alkalosis e.g.: Lab Value Name

CO2 22 ________________________________

HCO3 18 ________________________________

CO2 48 ________________________________

HCO3 28 ________________________________

Step#4: Putting it all together

• Once you determine which CO2 and HCO3 are alkalotic or acidotic, your baby’s last name must match the Daddy’s name.

Practice: pH PaCO2

PaHCO3 1st Name Middle Last Name Name 7.21 32 14

7.18 68 29

7.50 26 21

7.52 36 34

7.36 54 32

7.44 30 20

7.02 60 12

7.12 28 10

7.52 24 22

7.37 52 30

7.38 38 25

Answer Key: pH PaCO2

PaHCO3 1st Name Middle Last Name Name 7.21 32 14 a b a uncompensated metabolic acidosis 7.18 68 29 a a b uncompensated respiratory acidosis 7.50 26 21 b b a uncompensated respiratory alkalosis 7.52 36 34 b n b uncompensated metabolic alkalosis 7.36 54 32 n a b compensated respiratory acidosis 7.44 30 20 n b a compensated respiratory alkalosis 7.02 60 12 a a a uncompensated metabolic and respiratory acidosis 7.12 28 10 a b a uncompensated metabolic acidosis 7.52 24 22 b b n uncompensated respiratory alkalosis 7.37 52 30 n a b compensated respiratory acidosis 7.38 38 25 n n n normal