J Korean Soc Emerg Med.  1997 Sep;8(3):331-340.

The End Tidal Carbon Dioxide During Cardiopulmonary Resuscitation

• Chung SP
• Nam TS
• Lee HS
• Park CS
• Kim SJ

Abstract

BACKGROUND: The end-tidal carbon dioxide (ETCO2) is defined as a partial pressure of carbon dioxide at the end of an exhaled breath. And it has been found to correlate with cardiac output during cardiopulmonary resuscitation (CPR) in animal model. The purpose of this study is to determine that the assessment of ETCO2 could provide a highly sensitive predictor of return of spontaneous circulation (ROSC) during CPR.
METHODS
Prospective, observational study was performed from Oct 1996 to Mar 1997 at the Severance hospital. All patients were endotracheally intubated and connected immediately to mainstream capnography sensor. We measured ETCO2 with Escort II model 20100 monitor(Medical Data Electronics, Inc, USA). It works on the principle of nondispersed infrared absorption with radiometric single beam optics.
RESULTS
This study included 70 patients (52 were men) with a mean age of 54+/-15 years. ROSC was obtained in 43 patients. The initial ETCO2 averaged 15.5 +/-8.2 mmHg in survivors and 6.5+/-5.3 mmHg in nonsurvivors (p<0.01), and during the first 20 minutes of CPR, the maximal ETCO2 averaged 29.7+/-10.3 mmHg in survivors and 10.2+/-8.9 mmHg in nonsurvivors (p<0.01). ETCO2 was not significantly different in relation to initial rhythm, survival time after ROSC and possible cause of arrest. There is no cutoff value of ETCO2 satisfying greater than 90% of both sensitivity and specificity in predict ROSC. When maximal ETCO2 was less than 12 mmHg, we observed sensivity of 100% in predicting ROSC.
CONCLUSION
Our results demonstrate that ETCO2 measurement represents a valuable, noninvasive, and clinical tool for monitoring patients during CPR.

MeSH Terms

Absorption
Capnography
Carbon Dioxide*
Carbon*
Cardiac Output
Cardiopulmonary Resuscitation*
Humans
Models, Animal
Observational Study
Partial Pressure
Prospective Studies
Sensitivity and Specificity
Survivors
Carbon
Carbon Dioxide