The Value Of Volume-capnography Waveform-derived Parameters In The Monitoring Of Cardiopulmonary Resuscitation Quality And Prognosis

Aim:We aimed to investigate whether the ability of the two volumetric capnography-derived parameter-V’ CO2(the volume of C02 eliminated per minute),V’ CO2kg-1(the volume of CO2 eliminated per minute and per kg body weight)and the partial pression of end-tidal carbon dioxide(PETC02),in monitoring the quality of Cardiopulmonary resuscitation(CPR)and predicting the return of spontaneous circulation(ROSC)remains undisturbed by hyperventilation.Methods:12 3-4 month old landrace pigs were included in the experiment,and a randomized crossover control experiment was designed.CPR model was established by ventricular fibrillation(VF)induction.After 4 min of untreated VF,a 5-minute washout period was set for standard CPR.At the end of the previous phase,the animals were resuscitated in two successive stages.In the first stage,the basic life support of CPR was simulated,and only standard chest compression and respiratory support were given.The animals experienced four ventilation types(including one normal ventilation type and three hyperventilation types)in random order.In the second stage,advanced life support was simulated.In the previous stage,the last ventilation mode was used to ventilate.CPR was continued for 10 minutes or the experiment was stopped after the animals obtained ROSC.During the experiment,fundamental bio-indicators,hemodynamic indexes and Vcap-derived parameters were collected.Results:In the first stage of the experiment,generalized linear analysis revealed different ventilation types had no significant impact on V’ CO2,V’ CO2kg-1 or haemodynamics.However,PETC02 was significantly affected by the ventilation type and coronary perfusion pressure(P<0.05).The means±standard deviations of PETC02 decreased linearly with an increase in the respiratory rate(RR)and tidal volume(VT)(P<0.05).No significant differences in V’ CO2,V CO2kg-1 were observed between the three RR levels of ventilation types(P=0.274).Post-hoc analysis demonstrated the highest value of V’ CO2kg-1 in double VT hyperventilation(DVTH),having a significant difference with normal ventilation(NV)and triple RR hyperventilation(TRRH)(P<0.05).In the second stage of the experiment,7 out of 12 animals successfully achieved ROSC.The ROC curve was used to compare the ability of two parameters to predict the success of obtaining ROSC.The performance of the two parameters was better than that of PETCO2(0.80 vs.0.71).Conclusions:In the hyperventilation setting of CPR animal model,V’ CO2kg-1 performs better than PETCO2 in monitoring the quality of CPR and predicting ROSC during hyperventilation.Aim:We aimed to evaluate the partial pressure of end-tidal carbon dioxid(PETC02)and V’ CO2kg-1 as an indicator of the quality of chest compression(CC)and to predict the return of spontaneous circulation(ROSC)under stable ventilation status.Methods:12 3-4 month old landrace pigs were included in the experiment,and a randomized crossover control experiment was designed.Cardiopulmonary resuscitation(CPR)model was established by ventricular fibrillation(VF)induction.After 4 min of untreated VF,a 5-minute washout period was set for standard CPR.Following washout periods,each animal underwent two sessions of experiments:three types of CC quality for 5 minutes stages in the first session,followed by advanced life support,consecutively in two sessions,the same ventilation settings were used throughout the experiment.In the first stage,basic life support of CPR was simulated.The animals experienced three types of compression quality(including high quality,medium quality and low quality compression)in random order.In the second stage,advanced life support was simulated.All animals were compressed with high quality.Continue CPR for 10 minutes or stop the experiment after achieving ROSC.During the experiment,basic vital signs,hemodynamic indexes and related parameters of Vcap were collected.Results:In the first stage of the experiment,generalized linear analysis showed that different compression quality had significant effect on PETC02,V’ CO2kg-1,AOP,RAP and CBF,but had no significant effect on CPP(P<0.05).With the improvement of compression quality,PETCO2 and V’ CO2kg-1 also increased,there was significant difference between different groups(P<0.05).Spearman correlation analysis showed that PETCO2,V’CO2kg-1 and hemodynamics had significant correlation.In the second phase of the experiment,PETCO2 and V’ CO2kg-1 have similar ability in predicting ROSC,both AUC are 0.97.The optimal cutoff point in PETCO2 was 17.5 mmHg,which demonstrated a sensitivity of 0.89 and a specificity of 1.00.The optimal cutoff point in V’ CO2kg-1 was 2.06 ml min-1kg-1,which demonstrated a sensitivity of 0.82 and a specificity of 1.00.Conclusions:In the normal ventilation setting of CPR animal model,PETCO2 and V’ CO2kg-1 can accurately reflect the compression quality,and there is significant correlation between the two indicators and hemodynamics;both parameters can accurately predict ROSC.Aim:We aimed to evaluate the ability of a modified volumetric capnography(Vcap)-derived parameter,the ratio between the partial carbon dioxide end-tidal pressure(PETCO2)and the volume of carbon dioxide eliminated per minute and per kg of body weight(V’ CO2kg-1)(P/V),in detecting hyperventilation during cardiopulmonary resuscitation(CPR)by secondary analysis of experimental data from ventricular fibrillation animal resuscitation model.Methods:The experimental data of 12 3-4-month-old long-white porcine in the first part of this study were analyzed.Data of each animal in the first phase of the experiment were selected,including basic vital signs,ventilator related parameters,vcap-derived parameters and hemodynamic parameters.According to different ventilation modes,it was divided into the normal ventilation(NV)group,the double respiratory rate hyperventilation(DRRH)group,the double tidal volume hyperventilation(DVTH)group,and the triple respiratory rate hyperventilation(TRRH)group.The differences of Vcap-derived parameters were compared among the groups.The receiver operating characteristic(ROC)curve was drawn to assess the ability of Vcap derived parameters to identify hyperventilation.Results:The generalized linear mixing model suggests that different ventilation types have significant effects on Vcap derived parameters(P<0.05).The PETCO2 and P/V in NV group was significantly higher than that in DRRH group,DVTH group and TRRH group,with significant statistical difference between the groups(P<0.05).However no significant statistical difference was observed between DRRH group and TRRH group.The value of P/V reflected hyperventilation accurately and immediately,with an area under the curve of 0.98.The area under the curve for discerning the two-fold minute ventilation from three-fold minute ventilation is only 0.68.The optimal cut-off point of the P/V for discriminating hyperventilation from non-hyperventilation was 6.36,with a sensitivity and specificity of 0.99 and 0.89,respectively.Conclusions:The modified Vcap derived parameter P/V shows good performance in discriminating hyperventilation from non-hyperventilation and can quickly respond after hyperventilation.For monitoring changes in ventilation status during CPR,the P/V may be a valuable clinical indicator for monitoring ventilation status during CPR.