29 - Carbon dioxide pathophysiology

Summary

This chapter discusses the reduced and increased CO2 pressures and outlines some of the pathophysiology of CO2 production and transport, with special reference to capnography. Capnography has a special use in the assessment of patients for brain death with regard to the apnea test, wherein measurement of CO2 tensions are a component of assessing the viability of the brainstem. Any disruption in normal mitochondrial function manifests as diminished energy reserves and CO2 production, and is most rapidly evident in organs with high-energy requirements such as the brain, heart, kidney, and, especially, the eye. Carbonic anhydrase comprises a family name for a group of zinc-dependent enzymes that catalyze the reaction of bicarbonate and a proton to form water and CO2. Sodium bicarbonate is sometimes intravenously injected to treat acidemia in patients suffering from metabolic acidosis.