Thursday, February 15, 2024

EMS Patient Monitoring - Capnography 4

Understanding the capnography waveform is essential. A consistent waveform indicates proper ventilation, while irregularities may signal airway or respiratory issues.


Equipment Calibration: Regular calibration of capnography equipment is essential to maintain accuracy in CO2 measurements.

Interference with Nasal Cannula: Nasal cannulas may result in lower ETCO2 readings due to air dilution. Consider using an alternative sampling method if necessary.

Low Perfusion States: In low perfusion states, such as during cardiac arrest, capnography may be less reliable in reflecting true ETCO2 levels.

Temperature Compensation: Capnography measurements are temperature-dependent. Providers should be aware of the need for temperature compensation to ensure accurate readings.


Airway Anomalies: Some airway anomalies or pathologies may affect capnography readings. Providers should be cautious in interpreting results in such cases.

Equipment Malfunction: Malfunctions in the capnography equipment can lead to inaccurate readings. Regular maintenance and checks are necessary.

Rebreathing: Rebreathing or partial rebreathing masks can result in elevated ETCO2 levels, affecting the accuracy of monitoring.

Sampling Rate: Inadequate sampling rates may result in delayed detection of changes in ETCO2 levels. Ensure the capnography device has an appropriate sampling rate.

Pulmonary Embolism: In cases of massive pulmonary emboli, capnography may show a decrease in ETCO2 due to reduced perfusion to the lungs.

EMS providers should undergo proper training to interpret capnography data accurately and be aware of the limitations and special considerations in various clinical scenarios.

Regular education and updates on capnography technology are crucial to providing optimal patient care.

Further Reading:

Capnography: Principles and Practice by Michael K. Copeland

Capnography, King of the ABC’s: A Systematic Approach for Paramedics" by Troy Valente

Paramedic Care: Principles & Practice: by Bryan E. Bledsoe, Robert S. Porter, and Richard A. Cherry

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