Acid Base Balance
Patients with disorders affecting many different organ systems show abnormalities of acid-base metabolism. The rational diagnosis and treatment of these abnormalities commonly result in important therapeutic gains for the patient. Measurement of acid-base variables is required for the care of patients during cardiopulmonary bypass. Every Perfusionist involved in the care of seriously ill patients, regardless of specialty, needs to have a working knowledge of acid-base disturbances.
The clinical importance of acids and bases is related to several factors. Acids and bases affect the chemical behavior of water. Most chemical reactions within the body take place in water solutions, changes in the concentration of acids or bases have significant chemical effects. Hydrogen ions are highly mobile charged particles. Changes in the hydrogen ion concentration ultimately affect the distribution of such ions as sodium, potassium, and chloride in the cell. The hydrogen ion concentration influences the three-dimensional configuration of proteins. Because such confrontational changes affect the biochemical activity of proteins and because much of normal cell function depends on normal protein function, changes of hydrogen ion concentration are important. Enzymes exhibit optimal activity within a narrow range of pH.