Carbon dioxide monitoring in children—A narrative review of physiology, value, and pitfalls in clinical practice

Continuous capnography has been recognised as an essential monitoring device in all anesthetized patients, despite which airway device is in use, regardless of their location, as a measure to improve patient safety. Capnography is the non-invasive measurement of a sample of the exhaled carbon dioxide which has multiple clinical uses including as a method to confirm placement of a tracheal tube and/or to assess ventilation, perfusion and metabolism. Notably, capnography is used during routine paediatric anesthesia to assess ventilation and as a surrogate measure for arterial carbon dioxide pressure. The inaccuracies associated with these surrogate measures need to be considered to inform improved ventilation management of infants and children. This review highlights some major principles to understand the carbon dioxide elimination, the physiology of paediatric capnography, the clinical application and the limitations of capnography during anesthesia for neonates, infants and small children.