End Tidal Capnography

How to read the waveform​

What is ETCO2?

• End Tidal Carbon Dioxide is a tool used to determine how well a patient is ventilating and shows the product of gas exchange​​.
• Paramedics may use for monitoring ventilatory status, advanced airway confirmation (SGA, ET tube), discern possible patient deterioration, recognize ROSC and ascertain the quality of CPR.​​
• ETCO2 waveform capnography allows paramedics to monitor ventilatory status in real time. ​​
• Normal ETCO2 values are 35-45 mmHg. Pt's may become hypercapnic or hypocapnic based on their individual disease pathology.

ETCO2 Waveform

WAVEFORM CAPNOGRAPHY CAN BE BROKEN DOWNINTO 4 PHASES:​

• Phase 0 – Inspiratory upstroke​
  • Inspiration occurs here, leading to no reading for ETCO2​.
• Phase 1 – Expiratory upstroke (rise phase)​
  • The beginning of exhalation, there will be a drastic increase to the waveform as CO2 is exhaled​.
• Phase 2 – Alveolar Plateau​
  • This is the stage when the expired CO2 reaches the sensor. The end of the plateau phase is where the amount of carbon dioxide is measured​.
• Phase 3 –Inspiratory downstroke​
  • Rapid drop in the waveform as inspiration occurs leading to decreased CO2 and increased O2​.

ETCO2 Pearls

• ETCO2 allows for real time readings of the patient's respiratory status and allows paramedics to determine how well a patient is ventilating​.
• It is a non-invasive means to assess and recognize possible respiratory complications and possible further deterioration in certain patient populations​.
• A proper ETCO2 waveform tells paramedics how a patient is ventilating in different ways than the SPO2. ETCO2 and SPO2 used together can give providers a much larger snapshot as to what is really going on.

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