This course dives into why acid–base derangements happen, not just how to read the ABG. You’ll walk through the renal handling of bicarbonate, ammonium, and electrolytes, and see how increased acid production, impaired renal excretion, and bicarbonate loss drive metabolic acidosis—while chloride and potassium depletion help create and sustain metabolic alkalosis. By the end, you’ll be able to connect the underlying physiology to real-world perioperative scenarios, improving your ability to anticipate problems and fine-tune anesthetic management at the bedside.