Exhaled CO2 Parameters as a Tool to Assess Ventilation-Perfusion Mismatching during Neonatal Resuscitation in a Swine Model of Neonatal Asphyxia

Background End-tidal CO 2 (ETCO 2 ), partial pressure of exhaled CO 2 (PECO 2 ), and volume of expired CO 2 (VCO 2 ) can be continuously monitored non-invasively to reflect pulmonary ventilation and perfusion status. Although ETCO 2 ≥14mmHg has been shown to be associated with return of an adequate heart rate in neonatal resuscitation and quantifying the PECO 2 has the potential to serve as an indicator of resuscitation quality, there is little information regarding capnometric measurement of PECO 2 and ETCO 2 in detecting return of spontaneous circulation (ROSC) and survivability in asphyxiated neonates receiving cardiopulmonary resuscitation (CPR). Methods Seventeen newborn piglets were anesthetized, intubated, instrumented, and exposed to 45-minute normocapnic hypoxia followed by apnea to induce asphyxia. Protocolized resuscitation was initiated when heart rate decreased to 25% of baseline. Respiratory and hemodynamic parameters including ETCO 2 , PECO 2 , VCO 2 , heart rate, cardiac output, and carotid artery flow were continuously measured and analyzed. Results There were no differences in respiratory and hemodynamic parameters between surviving and non-surviving piglets prior to CPR. Surviving piglets had significantly higher ETCO 2 , PECO 2 , VCO 2 , cardiac index, and carotid artery flow values during CPR compared to non-surviving piglets. Conclusion Surviving piglets had significantly better respiratory and hemodynamic parameters during resuscitation compared to non-surviving piglets. In addition to optimizing resuscitation efforts, capnometry can assist by predicting outcomes of newborns requiring chest compressions.