End tidal CO₂ and cerebral oximetry for the prediction of return of spontaneous circulation during cardiopulmonary resuscitation.

Abstract

End Tidal CO₂ (ETCO₂) is a reasonable predictor of Return of Spontaneous Circulation (ROSC) in cardiac arrest (CA), though with many limitations. Cerebral Oximetry (CerOx) non-invasively measures brain O₂ saturation and correlates with flow. This study compares ETCO₂ and CerOx for ROSC prediction during both out of hospital (OHCA) and emergency department cardiac arrests (EDCA). We conducted a prospective study on CA patients resuscitated in the ED. ETCO₂ and CerOx simultaneously measured during ED CPR. Data was analyzed with logistic regression modeling and area under the curve (AUC). 176 patients were analyzed, 66.7% were witnessed, 52.8% had bystander CPR. EMS alert to ED arrival was 27.0 ± 10.6 min. Initial rhythm was 31.8% asystole, 27.8% PEA, 25.6% VF/VT with 26.1% achieving ROSC. AUC predictors of ROSC were: last 5 min trend [CerOx = 0.82 ; ETCO₂ = 0.74], delta first to last [CerOx = 0.86 ; ETCO₂ = 0.73], the penultimate minute [CerOx = 0.81 ; ETCO₂ = 0.76], and final minute [CerOx = 0.89 ; ETCO₂ = 0.77]. AUC comparison of simultaneous measurements (n = 125) revealed: last 5 min trend [CerOx = 0.80 ; ETCO₂ = 0.79], delta first to last [CerOx = 0.83 ; ETCO₂ = 0.75], penultimate minute [CerOx = 0.83 ETCO₂ = 0.74], and final minute [CerOx = 0.89 ; ETCO₂ = 0.75]. Our data shows, both ETCO2 and rSO2 are good predictors of ROSC. We found CerOx superior to ETCO₂ in predicting ROSC.