The term capnography refers to the noninvasive measurement of the partial pressure of carbon dioxide (CO2) in exhaled breath expressed as the CO2 concentration over time1. The relationship of CO2 concentration to time is graphically represented by the CO2 waveform, or capnogram1. Capnography provides information about CO2 production, pulmonary perfusion, alveolar ventilation, respiratory patterns, and elimination of CO2 from the anesthesia circuit and ventilator2.
Capnography and Anesthesia
"During anesthesia, there is an interplay between two components; the patient and the anesthesia administration device which is usually a circuit and a ventilator. The critical connection between the two components is either an endotracheal tube, LMA or a mask and the CO2 is typically monitored at this junction. In expired respiratory gases, capnography directly reflects the elimination of CO2 by the lungs to the anesthesia device. Indirectly, it reflects the production of CO2 by tissues and the circulatory transport of CO2 to the lungs." 2
Why Capnography Matters
According to an ASA closed claim study capnography and pulse oximetry together could have helped in the prevention of 93% of avoidable anesthesia mishaps 2.
The use of capnography matters because the anesthesiologist's main concern is to prevent hypoxia. Capnography aids in the detection of situations that could lead to hypoxia if left unchecked. Capnography also helps detect the onset of hypoxia so that measures can be taken to prevent brain damage.
Problems are detected by looking for changes in the capnogram and in end-tidal CO2. Capnogram shape changes can identify disease conditions. Changes in end-tidal CO2 or the maximum CO2 concentration at the end of each tidal breath can be used to assess disease severity and patient responses to treatment1.
Capnography and APA Guidelines
Capnography has become standard for patients receiving sedation. The American Dental Association (ADA), American Association of Oral and Maxillofacial Surgeons (AAOMS), and American Society of Anesthesiology require capnography for sedated patients.
To meet ADA guidelines capnography is required for Moderate Sedation, and Deep Sedation or General Anesthesia. Capnography is not currently required for Mild Sedation.
For more information about the specific guidelines for the use of sedation and General Anesthesia visit the ADA Anesthesia and Sedation page.
Recommended Capnography Devices
EDAN IM60 GT - The powerhouse of monitors. The device comes equipped with capnography as well as other required vital sign monitors. It includes a touch screen, the ability to record data digitally, data graphing, customizable data recording, customizable alarms, custom profiles, individual patient data storage, the ability to input and recall patient history, and a long list of other useful features.
Nonin RespSense Capnography Monitor - A portable standalone touchscreen EtCO2 and respiratory rate monitoring device that can supplement your existing monitoring equipment. The Nonin is recommended because it has fast detection, an easy to read display, it is easy to use, quiet, cost-effective, and it includes a three-year warranty.
1 - Carbon dioxide monitoring (capnography) - https://www.uptodate.com/contents/carbon-dioxide-monitoring-capnography
2 - Why Capnography? - http://www.capnography.com/capnography-introduction/why-capnography
3 - Sedation During Dental Procedures - http://www.capnography.com/capnosedation/capnography-in-dental-sedation-procedures
4 - Anesthesia and Sedation - Guidelines for the Use of Sedation and General Anesthesia by Dentists - https://www.ada.org/en/member-center/oral-health-topics/anesthesia-and-sedation