ABG

ABG

1. 1) Look at pH (7.35-7.45)

   • High = alkalosis, low = acidosis

2. 2) Look at CO2 (4.7-6kPa)

   • High (hypercapnia) or low? In keeping with pH? If so = respiratory prob, if not = compensating

3. 3) Look at the bicarb (24-26mmol/L)

   • High or low? In keeping with the pH? If so = metabolic prob, if not = compensating

4. 4) Look at O2 (10.5-13)

   • Low = hypoxia

5. 5) Look at the O2 & CO2 together

   • Type 1 resp failure: pO2 < 8, normal or low pCO2
   • Type 2 resp failure: pO2 < 8, pCO2 >6.5

6. Lactate measured by some machines, should be 0-2

7. Compensation

   • Respiratory: mins to hrs
   • Metabolic: days to a week

8. Differentials

   • Acidosis
     • Respiratory acidosis: low pH, high CO2, high bicarb
     • Metabolic acidosis: low pH, high CO2, high bicarb
   • Alkalosis
     • Respiratory alkalosis: high pH, low CO2, low bicarb
     • Metabolic alkalosis: high pH, normal or high CO2, high bicarb