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A capnograph is a monitoring device that measures carbon dioxide in exhaled breath and displays it as a waveform. The end-of-breath carbon dioxide value is called end-tidal carbon dioxide, or ETCO2. Capnography helps clinicians assess ventilation, airway placement, and breathing changes in real time. It is often used during anesthesia, sedation, emergency care, and ventilator monitoring.
read more about capnograph ...The device samples exhaled gas from the airway or breathing circuit. It measures carbon dioxide levels throughout the breathing cycle and displays a number with a waveform. The waveform shows how carbon dioxide rises and falls with each breath. Changes in the number or shape can signal breathing changes, airway obstruction, tube problems, or circulation changes.
A capnograph can be used during surgery, procedural sedation, intubation, mechanical ventilation, emergency resuscitation, and transport. It can help confirm that an endotracheal tube is in the airway rather than the esophagus. It can also help monitor whether a sedated patient is breathing enough. The results are reviewed with oxygen level, pulse, blood pressure, exam findings, and clinical context.
Capnography gives both a numerical ETCO2 value and a waveform pattern. A sudden loss of waveform can suggest disconnection, tube displacement, apnea, or equipment problems. A rising ETCO2 trend can reflect reduced ventilation or increased carbon dioxide production. A low value can happen with hyperventilation, poor circulation, leaks, or other clinical changes.
Capnography does not replace pulse oximetry, physical assessment, or clinical judgment. Oxygen levels can look normal for a short time even when ventilation is getting worse, so CO2 monitoring can give earlier warning in some settings. Sampling lines, adapters, moisture, secretions, or loose connections can affect readings. Staff should check the patient and equipment when the waveform changes unexpectedly.
No. A pulse oximeter estimates blood oxygen saturation, while a capnograph measures carbon dioxide in exhaled breath. They monitor different parts of breathing and circulation.
ETCO2 means end-tidal carbon dioxide. It is the carbon dioxide level measured at the end of an exhaled breath.
Capnography can show breathing changes before oxygen levels drop. This helps staff respond sooner if breathing becomes slow, shallow, or interrupted.
Yes. A consistent carbon dioxide waveform after intubation supports placement of the tube in the airway. Clinicians also use other checks to confirm tube position.
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