The three steps, in order of frequency, that should be used to interpret a blood gas measurement are:

Respiratory Acidosis
Evaluate the CO2 value, if it is high. This disorder is characterized by an elevation of CO2 due to hypoventilation, HCO3- increases as a compensatory response.
This alteration is due to hypoventilation and the consequence is hypercapnia.
Hypercapnia occurs as a result of inadequate ventilation, which may be due to the inability of the ventilatory pump to maintain ventilation, ventilatory pump failure due to respiratory disease, central nervous system depression, abnormal neuromuscular transmission or respiratory muscle dysfunction.
This leads to an inability to remove CO2 and increased levels of it in the arterial blood.

Metabolic Acidosis
In this disorder, low HCO3 should be assessed. It is characterized by low HCO3- < 22 mEq/L. Metabolic acidosis is produced by two ways: accumulation of fixed acids in the blood, in this case is given by tissue hypoxia which produces anaerobic metabolism and produces lactic acid, the result is the accumulation of H + which reacts with HCO3- achieving its decrease.
Due to the damping by increase of H+ during the metabolic acidosis, hyperventilation is produced by stimulation of the central and peripheral receptors, usually in 1 to 2 hours.

Respiratory alkalosis
It is the reduction of CO2
as a primary disorder; for evaluation
of this disorder should be assessed the CO2 is high or low. This disorder is characterized by a decrease in CO2 due to hyperventilation, the HCO3- decreases as a renal response
compensatory.

Metabolic alkalosis
In order to verify this disorder, one must evaluate whether the value of HCO3- is
normal, high or low. It is characterized by pH > 7.45, as an alteration
primary, there is an increase of HCO3- in blood plasma > of 26Meq/L, and an increase of PCO2 by compensatory hypoventilation.
This induces release of H+ from intracellular tampons
and later hypoventilation by inhibition of the centers respirators

Mnemonic

Mixed disorders

pH Ranges

Black: Acid
Grey: Balance
White: Alkalosis

Normal newborn gas values

Anion GAP

List of anions and cations

Practice the artery gases