Topic overview

Start with the big picture

The lesson organizes acid-base disorders by their primary change: bicarbonate rises or falls in metabolic disorders, while PaCO₂ rises or falls in respiratory disorders. It explains that compensation differs by cause: respiratory responses act quickly in metabolic disorders, whereas renal responses are slower in respiratory disorders, and neither fully normalizes pH. For metabolic acidosis, anion-gap assessment helps distinguish high-gap causes—including ketoacidosis, lactic acidosis, renal failure, and toxins—from normal-gap causes such as diarrhea and renal tubular acidosis. The lesson also classifies metabolic alkalosis as chloride-responsive or chloride-resistant and contrasts acute and chronic contexts for respiratory acidosis and alkalosis. These ideas are brought together in a quick framework for interpreting arterial blood gases.