Abstract Body: Introduction: Conventional cardiopulmonary resuscitation (CPR) guidelines fail to account for variability in the physiologic response to resuscitation potentially limiting effectiveness. End-tidal carbon dioxide (ETCO₂) reflects cardiac output during resuscitation and our prior work demonstrated that titrating CPR parameters based on ETCO₂ levels improved intra-arrest hemodynamics in a prolonged asphyxial model of cardiac arrest.
Research Question: Does ETCO₂ – guided CPR improve intra-arrest hemodynamics and outcomes in a pediatric ventricular fibrillation (VF) cardiac arrest swine model?
Methods: In this prospective, randomized study, 3.5–4.5 kg swine underwent 7.5 minutes of VF followed by 10 minutes of CPR. Animals were randomized to receive either standard CPR or ETCO₂-guided CPR. The standard CPR group followed AHA guidelines (compression rate of 100/min, depth 1/3 the anteroposterior diameter, and epinephrine administration every 4 minutes). In the ETCO_{2 -} guided group, the compression rate was increased by 10 compressions/minute for every minute that the ETCO₂ remained < 30 mmHg and the epinephrine administration interval was increased to as frequent as every 2 minutes to maintain ETCO₂ ≥30 mmHg. The primary outcomes were mean intra–arrest ETCO₂, diastolic blood pressure, and myocardial perfusion pressure. Secondary outcomes were the rate of return of spontaneous circulation, 3-day survival, and time-to-ROSC.

Results: The mean ETCO₂ over the first 10 min of resuscitation was similar between groups (25.6±0.6 vs. 25.5±0.6, p=0.99). The mean compression rate was higher in the ETCO_2-guided group (124±1.5 vs. 101±0.5, p<0.0001). During the first 10 minutes of CPR, there were no differences in the DBP or MPP between the two groups. The ETCO₂-guided group received significantly more epinephrine doses (4.2±0.3 vs.3.0 ± 0.0; p=0.003). ROSC was achieved in 10/10 (100%) of the ETCO₂-guided group vs. 9/11 (82%) of the standard CPR group(p=0.476). Time-to-ROSC and three-day survival were similar between the two groups.

Conclusion: In this short VF cardiac arrest model, use of ETCO₂ – guided CPR resulted in similar intra-arrest ETCO₂, DBP, and MPP as in the standard CPR group. Rates of ROSC were high in both CPR groups.There were no adverse effects of chest compression rates and epinephrine administration intervals outside of the recommended ranges in the ETCO₂ – guided group.