Effect Of Capnography Estimating Cardiopulmonary Resuscitation Quality And Prognosis In Cardiac Arrest

Objective: To observe changes of partial pressure of end tidal carbon dioxide(P_ETCO₂) in cardiac arrest?CA? patients during cardiopulmonary resuscitation?CPR?, and to investigate the clinical value of P_ETCO₂ as an indicator for estimating the quality of CPR and prognosis of CA patients.Methods: 89 CA patients in adult were included after admitted to emergency department of Tianjin medical university general hospital from February 2014 to September 2015. CPR was implemented according to 2010 American Heart Association?AHA? Guidelines for CPR and Emergency Cardiovascular Care. All of the clinical variables of the patients were collected during CPR, initial P_ETCO₂, average P_ETCO₂ and final P_ETCO₂ were also collected after CPR. SPSS22.0 and Medcalc11.4.2.0 software package were used for statistical analysis. We used receiver operating characteristic curve?ROC? analysis in the clinical value of initial P_ETCO₂, average P_ETCO₂ and final P_ETCO₂ in the patients with return of spontaneous circulation?ROSC? separately, then calculate the cutoff value. We also performed multivariate Logistic regression analysis in order to find independent risk factors which had important effect on prognosis in CA.Results: The data of initial P_ETCO₂, average P_ETCO₂ and final P_ETCO₂ in CA patients during CPR conformed to normal distribution respectively. Initial P_ETCO₂, average P_ETCO₂ and final P_ETCO₂ in the patients with ROSC were significant higher than that with no-ROSC?P<0.05?. There were significant differences in CPR time, epinephrine dose and sodium bicarbonate dose between ROSC and no-ROSC?P<0.05?, and there were no significant differences in age, sex, external cardiac compression mode?ECC?, assisted respiration mode and defibrillation number between ROSC and no-ROSC?P>0.05?. Initial P_ETCO₂, average P_ETCO₂ and final P_ETCO₂ in bare-handed ECC and that in mechanical ECC had no significant differences?P>0.05?, the result between artificial respiration and mechanical ventilation was the same?P>0.05?. Among the area under the ROC curve?AUC? in initial P_ETCO₂, average P_ETCO₂ and final P_ETCO₂ for estimating the patients with ROSC, final P_ETCO₂ was the largest one?0.896±0.043?, and there was no significant difference in the AUC between initial P_ETCO₂ and average P_ETCO₂?P>0.05?, the best cutoff in initial P_ETCO₂ was 23 mm Hg, average P_ETCO₂ was 22 mm Hg, final P_ETCO₂ was 30 mm Hg. There was no significant difference in initial P_ETCO₂ between the patients with survival to discharge and that with death?P>0.05?. Average P_ETCO₂ and final P_ETCO₂ in the patients with survival to discharge were significant higher than that with death?P<0.05?, but they were not independent factors for estimating the death of CA.Conclusion: 1. Initial P_ETCO₂, average P_ETCO₂ and final P_ETCO₂ can be used as an indicator for estimating ROSC in CA patients during CPR, final P_ETCO₂ has the maximum value, the best cutoff of final P_ETCO₂ is 30 mmH g. 2. CPR mode has no effect on initial P_ETCO₂, average P_ETCO₂ and final P_ETCO₂. 3. Initial P_ETCO₂, average P_ETCO₂ and final P_ETCO₂ are not associated with prognosis in CA.