How should acid-base disorders be diagnosed?

Identification of abnormalities of acid-base balance continues to be a core component of critical care practice. All acid-base disorders can be explained in terms of carbon dioxide (respiratory disorders), strong ions and weak acids (metabolic acid base disorders). Acidosis and alkalosis can be defined in terms of pH and hydrogen ion concentration. Respiratory acidosis is characterized by a low pH, a high PaCO₂ and a high. Respiratory alkalosis is characterized by a high pH, a low PaCO₂ and a low. Metabolic acidosis is associated with a low pH, a low PaCO₂, and a low: there is usually a reduction in the strong ion difference (SID). Metabolic alkalosis is associated with a high pH, a high PaCO₂, a high and either increased SID or reduced serum proteins (A_TOT). The majority of clinicians use analytic tools that are more than a half century old, and while these remain useful-providing rules of thumb that for simple acid-base disturbances-they are limited in complex critically ill patients. The modern electrochemical approach utilizes the full battery of standard laboratory tests to aid precision to diagnosis and enhances our understanding of acid-base chemistry.