Associations Between End-Tidal Carbon Dioxide During Pediatric Cardiopulmonary Resuscitation, CPR Quality, and Survival.

Background: Supported by laboratory and clinical investigations of adult cardiopulmonary arrest, resuscitation guidelines recommend monitoring end-tidal carbon dioxide (ETCO2) as an indicator of CPR quality but note that "specific values to guide therapy have not been established in children." Methods: This prospective observational cohort study was an NHLBI-funded ancillary study of children in the ICU-RESUS citation trial (NCT02837497). Hospitalized children (≤18 years of age and ≥37 weeks post-gestational age) who received chest compressions of any duration for cardiopulmonary arrest, had an endotracheal or tracheostomy tube at the start of CPR, and had evaluable intra-arrest ETCO2 data were included. The primary exposure was event-level average ETCO2 during the first 10 minutes of CPR (dichotomized as ≥20 mmHg vs. <20 mmHg based on adult literature). The primary outcome was survival to hospital discharge. Secondary outcomes were sustained return of spontaneous circulation (ROSC), survival to discharge with favorable neurologic outcome, and new morbidity among survivors. Poisson regression measured associations between ETCO2 and outcomes as well as the association between ETCO2 and other CPR characteristics: 1) invasively measured systolic and diastolic blood pressures and 2) CPR quality and chest compression mechanics metrics (i.e., time to CPR start; chest compression rate, depth, and fraction; ventilation rate). Results: Among 234 included patients, 133 (57%) had an event-level average ETCO2 ≥20 mmHg. After controlling for a priori covariates, average ETCO2 ≥20 mmHg was associated with higher incidence of survival to hospital discharge (86/133 (65%) versus 48/101 (48%); aRR 1.33, CI95 1.04 - 1.69, p=0.023) and ROSC (95/133 (71%) versus 59/101 (58%); aRR 1.22, CI95 1.00 - 1.49, p=0.046) compared with lower values. ETCO2 ≥20 mmHg was not associated with survival with favorable neurologic outcome or new morbidity among survivors. Average ETCO2 ≥20 mmHg was associated with higher systolic and diastolic blood pressures during CPR, lower CPR ventilation rates, and briefer pre-CPR arrest durations compared with lower values. Chest compression rate, depth, and fraction did not differ between ETCO2 groups. Conclusions: In this multicenter study of children with in-hospital cardiopulmonary arrest, ETCO2 ≥20 mmHg was associated with better outcomes and higher intra-arrest blood pressures, but not with chest compression quality metrics.