Sevography as a Mirror of Capnography: A Novel Perspective for Interpreting Respiratory Patterns in Ventilated Patients

Capnography has been the cornerstone of respiratory monitoring in anaesthetic and critical care settings, providing real-time insights into ventilation, metabolism and circulation. Alongside this, the graphical representation of volatile anaesthetic agents-Sevography has traditionally been used to titrate anaesthetic depth. However, recent observations highlight a new utility of sevographs in their ability to reflect respiratory patterns as mirror images of capnograms, including spontaneous breaths during sevoflurane induction, downslope in expiration and curare cresting during mechanical ventilation with the vaporiser switched-on setting. This review explores the physiological principles behind this mirror relationship, its clinical implications in detecting various mirror imaging of capnography and its value as a supplementary monitoring tool, particularly beneficial for anaesthesiologist managing ventilated patients.