1. check the pH; normal pH at term is 7.2-7.3; if less than 7.2, it's acidosis
2. check pCO2; if >60 it's respiratory acidosis
3. check base deficit/excess; if it is <-12 or >12 it is metabolic acidosis; body is trying to buffer acids with bicarb
4. if both pCO2 and base deficit are abnormal it's mixed which means acute injury and long term issue