The Ultimate Vital Sign? Importance of Capnography in EMS Joshua Erdman, BS, CCEMT-P UW Emergency Education Center

CO2 O2 CO2 O2 The full cycle

CO2 O2 CO2 O2 The full cycle and our other vital signs RR Pulse EKG BP Pulse ox Capnography

The full cycle Measuring CO2 allows us to look at: –Ventilation –Perfusion –Cellular metabolism And all instantly!

Capnography Technology uses the Infrared absorbing capability of CO2 to determine the amount in a sample of air Gives us a measurement in mmHg Can graph this amount over time

Technology Two types –Mainstream Advantage: Fast Disadvantages: Bulky, usually only for intubated patients –Sidestream Advantages: Small samples, able to be used for spontaneous breathers Disadvantages: Slight time delay (<0.5 seconds)

Normal Capnogram

Capnogram Waveform PhaseTermedVariablesGas from phase IA→BbaselineA = completion of inspirationLarge airways Oropharynx nasopharynx B = beginning of expiration phase IIB→Cexpiratory upstroke C = slowing of exhaled flowIntermediate airways mixes with phase I air phase IIIC→Dalveolar plateauD = end expiration = PET CO2 Mixed gas displaced by alveolar gas phase IVD→Einspiratory downstroke E= end inspirationInspiratory gas has little CO2

Typical capnogram

Capno vs. Pulse ox

Intubations The #1 reason most paramedics know to use capnography AHA now identifies as the BEST way to confirm your tube (2010 guidelines)

Sudden change while bagging…

Sudden decrease!

Ventilation rates Normal value should be mmHg When ventilating, –if too LOW, you need to SLOW –if too HIGH, you need to FLY (go faster) ETCO2 Vent. rate

What the…?

What’s going on here?

Exponential decrease in CO2

CPR in progress

CPR uses Effective compressions ROSC Termination of CPR Should I even have started?

Spontaneous breathers Asthma vs. hyperventilation

Hyperventilation

Bronchospasm

Spontaneous breathers Overdose CHF Ketoacidosis Sepsis Hyperthermia MI, especially right-sided or inferior wall

Hmmm…

In summary…. Legal defense for intubations Immediate indication of changes in ventilation or perfusion Many clinical diagnosis possibilities when taken in consideration of other signs and symptoms

Thanks! Joshua Erdman UW Emergency Education Center