Significance of End-Tidal Carbon-Dioxide Monitoring as a Prognostic Indicator of Successful Resuscitation During Cardiopulmonary Resuscitation: Analysis According to Cause of Arrest

Eo, Eun Kyung; Ahn, Ki Ok; Kim, Jung Yeon; Cheon, Young Jin; Jung, Koo Young

Abstract

BACKGROUND: In recent years, there has been increasing interest in the use of capnometry, the noninvasive, continuous measurement of end-tidal carbon dioxide(ETCO2) in expired air during CPR. The purpose of this study is to determine the significance of ETCO2 monitoring according to immediate cause of arrest during CPR as a prognostic indicator of successful resuscitation and survival.
METHODS
A prospective, clinical study was performed from May 1997 to December 2000 at the Department of Emergency Medicine, Ewha Womans University Mokdong Hospital. The study included 220 patients(231cases). All patients were immediately connected to a mainstream capnometer sensor between the tube and the bag after endotracheal intubation using an infrared capnometer.
RESULTS
The 107 patients(46.3%) with return of spontaneous circulation(ROSC) had higher maximal ETCO2 during CPR than the 113 patients without ROSC(31.0+/-19.4 vs 11.7+/-9.4 mmHg, P=0.000). The ETCO2 was not significantly different in relation to age, initial rhythm, and survival time after ROSC, but there was a significant difference in the immediate cause of arrest in the ROSC group(respiratory arrest: 4 0 . 2+/-23.5 mmHg, P=0.000). In case of cardiac arrest due to trauma, maximal ETCO2 was not significant in the ROSC group compared with the non-ROSC group(18.2+/-16.6 vs 10.8+/-7.5 mmHg, P=0.208). When maximal ETCO2 was less than 10 mmHg, we observed a sensitivity of 94.4% and a specificity of 39.5% in predicting ROSC. There were 6 patients with ROSC even though the maximal ETCO2 was less than 10 mmHg.
CONCLUSION
Continuous ETCO2 monitoring during CPR may be noninvasive and valuable predictor of successful resuscitation and survival from cardiac arrest. However, ETCO2 should not be used as a single indicator for either cardiac arrest due to trauma or withdrawal of CPR.