Quick Take: Surfing the capnography waveform

Jon Puryear presented an engaging and hands-on session that stressed understanding normal waveforms to recognize what’s abnormal


Surfing the Capnography Waveform, presented by Jon Puryear at EMS Today 2015 in Baltimore, Md. taught the basics of capnography and gave student hands-on opportunities with Phillips Heartstart MRX monitors. Puryear, a long-time paramedic and educator from Texas, is a dynamic presenter that keeps the audience engaged and interested.

Overview: Know normal to understand abnormal

Use capnography, one of the best assessment tools for EMS since the EKG, to help diagnose and treat patients. Capnography should be utilized on all major medical and trauma patients, regardless of if they are intubated or not, to assess the patient and determine the effectiveness of interventions.

A mix of EMTs and paramedics in the session learned that capnography is a good tool for any level of EMS provider. Hands-on activities helped attendees understand normal and abnormal waveforms, as well as the causes of an abnormal waveform.

Memorable quotes

"I have been using capnography since the 1990s. Today I amazed at how little capnography is used in EMS and more amazed that capnography is used even less in the hospital."

"If you don't know normal you will never pick up on abnormal."

Key takeaways

  • Capnography findings can change our urgency in assessing and treating the patient.
  • Understanding physiology of respiration and perfusion is important to knowing why to use the assessment tools – SpO2 and EtCO2 – and what they tell us.
  • EMS providers need to know normal EtCO2 level, 35 to 45 mmHg, and waveform to be able to identify abnormal. As the patient inhales EtCO2 is 0 mmHg. The waveform doesn't form until the patient begins to exhale and after atmospheric air is expelled from the respiratory tract dead space.
  • In the normal capnography waveform there are four phases. Phase 1: inhalation, Phase 2: beginning (ascending) of exhalation, Phase 3: alveolar plateau as air is exhaled, Phase 4: inhalation resumes at the end-tidal point.
  • Use capnography on non-intubated patients, especially any patient with significant or severe medical illness or traumatic injury.
  • Respiratory distress explained: the patient is moving air in/out and is able to compensate for the medical problem causing the distress.
  • Respiratory failure: the patient is still moving air, but not adequately for respiration – the exchange of gas. The patient is unable to compensate for their underlying problem.
  • Respiratory arrest: The patient is not moving any air. EMS ventilates the patient.

Keep learning

When discussing his long career in EMS Puryear has realized there is always more to learn. "The more that I know the less I really know," said Puryear. 

Visit JonPuryear.com to learn more about Puryear's education programs.

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