Complex acid-base imbalance

Mixed Acid-Base Disturbances refers to two or more simple acid-base disorders. When mixed acid-base disorders occur, the original compensatory response no longer exists, and the pathophysiological changes are more complicated, and the clinical manifestations may be atypical. Therefore, it is necessary to make a preliminary diagnosis by carefully asking the medical history and analyzing the results of blood gas analysis. There can be multiple combinations of mixed acid-base disorders, but obviously it is not possible to have a combination of respiratory acidosis and respiratory alkalosis. When the two primary disorders cause the pH to change in the same direction, the deviation of the pH from the normal is more significant. For example, patients with metabolic acidosis and respiratory acidosis have lower pH values ​​than a single disorder. When the two obstacles cause the pH to change in the opposite direction, the plasma pH value depends on one of the dominant obstacles, and the magnitude of the change is not as large as that of a single obstacle because it is offset by another. If the two obstacles cause opposite pH changes to exactly offset each other, the patient's plasma pH can be normal, such as metabolic acidosis and respiratory alkalosis.