Capnography: Difference between revisions
No edit summary
Line 14: Line 14:
**ETCO2 ≥ PCO2
**ETCO2 ≥ PCO2
*Indirectly measures overall metabolism (or lack there of in cardiac arrest)
*Indirectly measures overall metabolism (or lack there of in cardiac arrest)
===Capnogram Overview===
[[File:Capnogram.jpg|400px|Typical waveform of a capnogram]]
*Exhalation will first expel dead space air (Phase I)
*Then a rapid rise in CO2 rich air is noted (Phase II)
*This is followed by a more gradual increase in CO2 (Phase III)
*The curve peaks at the end of Phase III which is noted as the End-Tidal CO2 measurement
*Inhalation follows (Phase 0 or IV)




==Uses==
==Airway Monitoring==
===Airway===
*Ensure adequate BVM ventilation
*Ensure adequate BVM ventilation
*Assess for ETT placement using presents of measurable ETCO2 and waveform
*Assess for ETT placement using presents of measurable ETCO2 and waveform
**In out of hospital use, this had SN 1.0 and SP 1.0 in detected good placement<ref>Silvestri, S, et al. The effectiveness of out-of-hospital use of continuous end-tidal carbon dioxide monitoring on the rate of unrecognized misplaced intubation within a regional emergency medical services system. Ann Emerg Med. 2005; 45(5):497-503.</ref>
**In out of hospital use, this had SN 1.0 and SP 1.0 in detected good placement<ref>Silvestri, S, et al. The effectiveness of out-of-hospital use of continuous end-tidal carbon dioxide monitoring on the rate of unrecognized misplaced intubation within a regional emergency medical services system. Ann Emerg Med. 2005; 45(5):497-503.</ref>


===CPR===
==Cardiac Arrest Monitoring==
*Ensure adequate chest compressions
*Ensure adequate chest compressions
**ETCO2 10-20mmHg signifies high quality chest compressions<ref>Kodali, BS, et al. Capnography during cardiopulmonary resuscitation: Current evidence and future directions. J Emerg Trauma Shock. 2014; 7(4):332–340.</ref>
**ETCO2 10-20mmHg signifies high quality chest compressions<ref>Kodali, BS, et al. Capnography during cardiopulmonary resuscitation: Current evidence and future directions. J Emerg Trauma Shock. 2014; 7(4):332–340.</ref>
Line 32: Line 38:
**ETCO2 level of 10mmHg or less after 20 min of CPR predicts death<ref>Eckstein, M, et al. End-Tidal CO2 as a Predictor of Survival in Out-of-Hospital Cardiac Arrest. Prehospital and Disaster Medicine. 2011; 26(3):148-150.</ref><ref>Levine, R, End-tidal Carbon Dioxide and Outcome of Out-of-Hospital Cardiac Arrest. NEJM.1997.  337(5):301-6.</ref>
**ETCO2 level of 10mmHg or less after 20 min of CPR predicts death<ref>Eckstein, M, et al. End-Tidal CO2 as a Predictor of Survival in Out-of-Hospital Cardiac Arrest. Prehospital and Disaster Medicine. 2011; 26(3):148-150.</ref><ref>Levine, R, End-tidal Carbon Dioxide and Outcome of Out-of-Hospital Cardiac Arrest. NEJM.1997.  337(5):301-6.</ref>


===Procedural Sedation===
==Procedural Sedation Monitoring==
*Pulse-ox has a lag time of sec to mins
*Pulse-ox has a lag time of sec to mins
*Capnography will show real-time respiratory changes and apnea
*Capnography will show real-time respiratory changes and apnea
Line 38: Line 44:




==Capnogram==
[[File:Capnogram.jpg|400px|Typical waveform of a capnogram]]
*Exhalation will first expel dead space air (Phase I)
*Then a rapid rise in CO2 rich air is noted (Phase II)
*This is followed by a more gradual increase in CO2 (Phase III)
*The curve peaks at the end of Phase III which is noted as the End-Tidal CO2 measurement
*Inhalation follows (Phase 0 or IV)


==See Also==
==See Also==

Revision as of 11:42, 20 October 2015

Background

  • End-tidal CO2 monitors can be qualitative or quantitative
    • Qualitative include calorimety devices (CO2 = blue, No CO2 = yellow)
    • Quantitative include devices that give numeric values
      • Mainstream (or inline) CO2 monitors are placed within the closed circuit of the ventilator (or BVM)
      • Sidestream CO2 monitors use special NC to detect CO2

Basics

  • Capnography measures the amount of exhaled CO2
  • ETCO2 of 35-45mmHg is considered normal
    • <35mmHg = Hypocapnia or Hyperventilation
    • >45mmHg = Hypercapnia or Hypoventilation
  • Directly measure the function of ventilation (not oxygenation)
    • ETCO2 ≥ PCO2
  • Indirectly measures overall metabolism (or lack there of in cardiac arrest)

Capnogram Overview

Typical waveform of a capnogram

  • Exhalation will first expel dead space air (Phase I)
  • Then a rapid rise in CO2 rich air is noted (Phase II)
  • This is followed by a more gradual increase in CO2 (Phase III)
  • The curve peaks at the end of Phase III which is noted as the End-Tidal CO2 measurement
  • Inhalation follows (Phase 0 or IV)


Airway Monitoring

  • Ensure adequate BVM ventilation
  • Assess for ETT placement using presents of measurable ETCO2 and waveform
    • In out of hospital use, this had SN 1.0 and SP 1.0 in detected good placement[1]

Cardiac Arrest Monitoring

  • Ensure adequate chest compressions
    • ETCO2 10-20mmHg signifies high quality chest compressions[2]
  • ROSC
    • Attaining ROSC is associated with an ETCO2 jump 10mmHg with ROSC (13.5 on average)[3]
    • CPR does not have to be stopped for pulse checks
    • Loss of ROSC can be determined by a significant drop signifies drop in ETCO2
  • Prognosis
    • ETCO2 level of 10mmHg or less after 20 min of CPR predicts death[4][5]

Procedural Sedation Monitoring

  • Pulse-ox has a lag time of sec to mins
  • Capnography will show real-time respiratory changes and apnea
  • ETCO2 monitoring detects clinically signifcant respiratory events before SPO2 or clinically noted apnea/hypoventilation[6]


See Also

Intubation Procedural sedation

External Links

http://www.capnography.com/

References

  1. ↑ Silvestri, S, et al. The effectiveness of out-of-hospital use of continuous end-tidal carbon dioxide monitoring on the rate of unrecognized misplaced intubation within a regional emergency medical services system. Ann Emerg Med. 2005; 45(5):497-503.
  2. ↑ Kodali, BS, et al. Capnography during cardiopulmonary resuscitation: Current evidence and future directions. J Emerg Trauma Shock. 2014; 7(4):332–340.
  3. ↑ Grmec, S, et al.Utstein style analysis of out-of-hospital cardiac arrest--bystander CPR and end expired carbon dioxide. Resuscitation. 2007; 72(3):404-14.
  4. ↑ Eckstein, M, et al. End-Tidal CO2 as a Predictor of Survival in Out-of-Hospital Cardiac Arrest. Prehospital and Disaster Medicine. 2011; 26(3):148-150.
  5. ↑ Levine, R, End-tidal Carbon Dioxide and Outcome of Out-of-Hospital Cardiac Arrest. NEJM.1997. 337(5):301-6.
  6. ↑ Burton, JH, et al. Does End-Tidal Carbon Dioxide Monitoring Detect Respiratory Events Prior to Current Sedation Monitoring Practices. Academic Emergency Medicine. 2006; 13:500–504.
Retrieved from "https://www.wikem.org/w/index.php?title=Capnography&oldid=47494"