A Novel Predictor of Unsustained Return of Spontaneous Circulation in Patients in Cardiac Arrest Through a Combination of Capnography and Pulse Oximetry

BACKGROUND:Unsustained return of spontaneous circulation (ROSC) is a critical barrier to survival in cardiac arrest patients. This study examined whether end-tidal carbon dioxide (ETCO2) and pulse oximetry photoplethysmogram (POP) parameters can be used to identify unsustained ROSC. METHODS:We conducted a multicenter observational prospective cohort study of consecutive patients with cardiac arrest from 2013 to 2014. Patients' general information, ETCO2, and POP parameters were collected and statistically analyzed. RESULTS:The included 105 ROSC episodes (from 80 cardiac arrest patients) comprised 51 sustained ROSC episodes and 54 unsustained ROSC episodes. The 24-hour survival rate was significantly higher in the sustained ROSC group than in the unsustained ROSC group (29.2% vs. 9.4%, P<0.05). The logistic regression analysis showed that the difference between after and before ROSC in ETCO2 (ΔETCO2) and the difference between after and before ROCS in area under the curve of POP (ΔAUCp) were independently associated with sustained ROSC (odds ratio [OR]=0.931, 95% confidence interval [95% CI] 0.881-0.984, P=0.011 and OR=0.998, 95% CI 0.997-0.999, P<0.001). The area under the receiver operating characteristic curve of ΔETCO2, ΔAUCp, and the combination of both to predict unsustained ROSC were 0.752 (95% CI 0.660-0.844), 0.883 (95% CI 0.818-0.948), and 0.902 (95% CI 0.842-0.962), respectively. CONCLUSION:Patients with unsustained ROSC have a poor prognosis. The combination of ΔETCO2 and ΔAUCp showed significant predictive value for unsustained ROSC.