Changes of end-tidal carbon dioxide during cardiopulmonary resuscitation from ventricular f ibrillation versus asphyxial cardiac arrest

BACKGROUND: Partial pressure of end-tidal carbon dioxide(PETCO2) has been used to monitor the effectiveness of precordial compression(PC) and regarded as a prognostic value of outcomes in cardiopulmonary resuscitation(CPR). This study was to investigate changes of PETCO2 during CPR in rats with ventricular fi brillation(VF) versus asphyxial cardiac arrest.METHODS: Sixty-two male Sprague-Dawley(SD) rats were randomly divided into an asphyxial group(n=32) and a VF group(n=30). PETCO2 was measured during CPR from a 6-minute period of VF or asphyxial cardiac arrest.RESULTS: The initial values of PETCO2 immediately after PC in the VF group were signifi cantly lower than those in the asphyxial group(12.8±4.87 mmHg vs. 49.2±8.13 mmHg, P=0.000). In the VF group, the values of PETCO2 after 6 minutes of PC were significantly higher in rats with return of spontaneous circulation(ROSC), compared with those in rats without ROSC(16.5±3.07 mmHg vs. 13.2±2.62 mmHg, P=0.004). In the asphyxial group, the values of PETCO2 after 2 minutes of PC in rats with ROSC were signifi cantly higher than those in rats without ROSC(20.8±3.24 mmHg vs. 13.9±1.50 mmHg, P=0.000). Receiver operator characteristic(ROC) curves of PETCO2 showed signifi cant sensitivity and specifi city for predicting ROSC in VF versus asphyxial cardiac arrest.CONCLUSIONS: The initial values of PETCO2 immediately after CPR may be helpful in differentiating the causes of cardiac arrest. Changes of PETCO2 during CPR can predict outcomes of CPR.