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Abstract

Introduction: During cardiopulmonary resuscitation (CPR), end tidal carbon dioxide (PetCO2) is used to assess the quality of compressions, return of spontaneous circulation (ROSC), and the futility of continued resuscitative efforts. For out-of-hospital cardiac arrest, the first measured etCO2 correlates with the etiology of arrest, as well as likelihood of ROSC and survival. Previous data from our institution documented a relationship between PetCO2 and outcome for ventricular fibrillation arrest. This has not been explored for pulseless electrical activity (PEA) arrest in the inpatient setting. Methods: This study was performed in two urban, academic inpatient hospitals. Patients were enrolled from July 2009-July 2013. A comprehensive database of all inpatient resuscitative events is maintained at these institutions, including demographic, clinical, and outcomes data. Arrests are stratified by primary etiology of arrest using a priori criteria. Inpatients with PEA arrest for whom recorded PetCO2 was available were included in the analysis. Capnography data obtained after ROSC and/or more than 10 minutes after initiation of CPR were excluded. Multivariable logistic regression was used to explore the association between initial PetCO2 >20 mmHg and both ROSC and survival-to-discharge. Results: A total of 50 patients with PEA arrest and pre-ROSC capnography were analyzed. CPR continued an average of 11.8 minutes after initial PetCO2 was recorded confirming absence of ROSC at time of measurement. Initial PetCO2 was higher in patients with versus without eventual ROSC (25.3 ± 14.4 mmHg versus 13.4 ± 6.9 mmHg, p=0.003). After adjusting for age, gender, and arrest location (ICU versus non-ICU), initial PetCO2 >20 mmHg was associated with increased likelihood of ROSC (adjusted OR 4.8, 95% CI 1.2-19.2, p=0.028). Initial PetCO2 was not significantly associated with survival-to-discharge (p=0.251). Conclusions: Initial PetCO2 >20 mmHg during CPR was associated with ROSC but not survival-to-discharge among inpatient PEA arrest victims. This analysis is limited by relatively small sample size.