160 - Acid-Base Disorders

Chemical Buffering Extracellular buffers, including plasma proteins, phosphates, and bicarbonate, are the earliest defense against acidosis. The most prominent extracellular buffer is bicarbonate, which is highly abundant and acts as a dynamic buffer by independently regulating Pco2 through changes in alveolar ventilation. This feature increases buffering capacity by more than 10-fold. Buffering also occurs within the intracellular compartment but is delayed as H+ equilibrates over a period of hours. Intracellular buffers, including bone, inorganic phosphates, proteins, and hemoglobin, are eventually responsible for more than 50% of the overall chemical buffering capacity.