Understanding arterial blood gases.

Arterial blood gases are useful in establishing acid-base status, determining the degree of impairment of the lungs as a gas exchanger, diagnosing such important phenomena as pulmonary emboli and implementing or adjusting oxygen therapy. The balance among H+, HCO3- and CO2 is represented by the equation H+ + HCO3- in equilibrium CO2 + H2O. Primary alterations of either component of the left-hand side of the equation result in metabolic acid-base balance disturbances; primary alterations of CO2 result in respiratory acid-base balance disturbances.