End-tidal carbon dioxide output in manual cardiopulmonary resuscitation versus active compression-decompression device during prehospital quality controlled resuscitation: a case series study

Background Active compression–decompression (ACD) devices have enhanced end-tidal carbon dioxide (ETCO 2 ) output in experimental cardiopulmonary resuscitation (CPR) studies. However, the results in out-of-hospital cardiac arrest (OHCA) patients have shown inconsistent outcomes, and earlier studies lacked quality control of CPR attempts. We compared manual CPR with ACD-CPR by measuring ETCO 2 output using an audiovisual feedback defibrillator to ensure continuous high quality resuscitation attempts. Methods 10 witnessed OHCAs were resuscitated, rotating a 2 min cycle with manual CPR and a 2 min cycle of ACD-CPR. Patients were intubated and the ventilation rate was held constant during CPR. CPR quality parameters and ETCO 2 values were collected continuously with the defibrillator. Differences in ETCO 2 output between manual CPR and ACD-CPR were analysed using a linear mixed model where ETCO 2 output produced by a summary of the 2 min cycles was included as the dependent variable, the patient as a random factor and method as a fixed effect. These comparisons were made within each OHCA case to minimise confounding factors between the cases. Results Mean length of the CPR episodes was 37 (SD 8) min. Mean compression depth was 76 (SD 1.3) mm versus 71 (SD1.0) mm, and mean compression rate was 100 per min (SD 6.7) versus 105 per min (SD 4.9) between ACD-CPR and manual CPR, respectively. For ETCO 2 output, the interaction between the method and the patient was significant (P 2 output was higher with manual CPR in 6 of the 10 cases. Conclusions This study suggests that quality controlled ACD-CPR is not superior to quality controlled manual CPR when ETCO 2 is used as a quantitative measure of CPR effectiveness. Trial registration number NCT00951704; Results.