ABG INTERPRETATION Flashcards
ABG INTERPRETATION
1- Check pH
2- Check HCO3 & pCO2
3- Determine the primary & compensating disorder
4- Degree of compensation (check pH)
5- Check oxygenation
6- Final interpretation
Normal pH
pH = 7.35 – 7.45
less than_____ = acidosis
more than_____ = alkalosis
7.35
7.45
If pH is not given in the problem, calculate the pH using _______
Henderson-Hasselbalch Equation
In Henderson-Hasselbalch equation
wherein: pk’ is____ (constant)
6.1
Dissolved carbon dioxide (DCO₂)
If dC02 is given, calculate the pH using this formula:
STEP 2 Evaluate the ventilation (lungs)
= respiratory Alkalosis
= respiratory Acidosis
pCO2 = 35 – 45 mm Hg
< 35
> 45
STEP 2
Evaluate the metabolic process (kidneys)
= metabolic acidosis
= metabolic alkalosis
[HCO3-] = 22 – 26 mmol/L (mEq/L)
< 22
> 26
STEP 3
Determine which is the primary and compensating disorder
• To assess whether primary problem is respiratory or metabolic in origin, compare changes of____ and ____ from baseline
• If the change In HCO2 from baseline is larger, then the problem Is primarily_____ and vice versa
HCO2 and pCO2
metabolic
pCO2
partial pressure of carbon dioxide
HCO3
Bicarbonate
STEP 4 Determine the degree of compensation:
ABG INTERPRETATION
a. non-compensatory
-
c. complete compensation
7.31 – 7.34 acidosis
7.46 – 7.49 alkalosis
= Implies that the pH is approaching normal
Partial
= Implies that the pH has returned to the normal range
Complete
STEP 5
Evaluate the degree of oxygenation
Normal range
(adequate oxygenation)
pO2 = 80 – 110 mm Hg
