Capnography Measurement of exhaled carbon dioxide can be used to confirm ETT placement, for safer procedural sedation, to guide resuscitation, and to monitor cardiac & pulmonary physiology. • PETCO2 - End-tidal CO2 (what's measured by capnography) • PACO2 - Alveolar CO2 • PvCO2 - Mixed venous CO2 • PaCO2 - Arterial CO2 (what's measured on an ABG) The Capnograph waveform is composed of 4 phases • Phase I — anatomical dead space ventilation • Phase II — dead space mixed with alveolar ventilation • Phase Ill — alveolar ventilation (where ETC02 measured) • Phase IV — end of exhalation Specific capnograph patterns: • Downsloping phase III: copd • Curare cleft - patient dysynchrony during mechanical ventilation breath • Prolonged phase II/III: bronchospasm, airway obstruction, copd • Dimorphic phase II/III: right mainstem intubation, single lung transplant • Cardiac oscillations: hypovolemia, hypoventilation • Prominent phase IV: obesity • Sudden drop in ETCO2: arrythmia, pe Nick Mark MD @nickmmark #Capnography #interpretation #waveforms #patterns #diagnosis #pulmonary #ETCO2
