Simple and mixed acid-base disorders
- Michael Emmett, MD
Michael Emmett, MD
- Editor-in-Chief — Nephrology
- Section Editor — Fluid and Electrolytes
- Chief of Internal Medicine
- Baylor University Medical Center
- Biff F Palmer, MD
Biff F Palmer, MD
- Professor of Internal Medicine
- University of Texas Southwestern Medical Center
Each day, adults generate large amounts of acids that must be expired, excreted, metabolized to non-charged neutral molecules, and/or buffered to avoid fatal acidemia. These acids are of three major classes:
●Approximately 15,000 mmol (considerably more with exercise) of carbon dioxide (CO2) is produced each day, which combines with water to form carbonic acid (H2CO3).
●Metabolic reactions generate several thousand mmol per day of organic acids, such as lactic acid and citric acid. These acids are metabolized to neutral products (such as glucose) and to CO2 and water. Normally, the generation and utilization rates of these organic acids are equal so that their steady state concentration in the extracellular fluid is relatively low and stable.
●Approximately 50 to 100 meq of nonvolatile acid is produced each day (mostly sulfuric acid derived from the metabolism of sulfur-containing amino acids in the diet).
Acid-base balance is maintained by normal pulmonary excretion of carbon dioxide, metabolic utilization of organic acids, and renal excretion of nonvolatile acids.
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- NORMAL VALUES ACCORDING TO SITE OF SAMPLING
- Arterial blood gas sample
- Peripheral venous blood gas sample
- Central venous sample
- DEFINITIONS OF ACID-BASE DISORDERS
- COMPENSATORY RESPIRATORY AND RENAL RESPONSES
- General principles
- Metabolic acid-base disorders
- - Metabolic acidosis
- - Metabolic alkalosis
- Respiratory acid-base disorders
- - Respiratory acidosis
- - Respiratory alkalosis
- Initial evaluation
- - Case 1
- - Case 2
- Mixed acid-base disorders
- - Case 3