End-tidal carbon dioxide (ETCO2) and ventricular fibrillation amplitude spectral area (AMSA) for shock outcome prediction in out-of-hospital cardiac arrest. Are they two sides of the same coin?

Predefibrillation end-tidal CO2and defibrillation success in out-of-hospital cardiac arrest: an observational cohort study

“…This was consistent when analyses included all available ETCO 2 readings, as well as when only the first available measurement was used. This is in contrast to previous studies using only advanced airways which have shown that predefibrillation ETCO 2 for all shocks can predict defibrillation success resulting in VF termination or ROSC 11–14. Our ability to measure predefibrillation ETCO 2 readings through BVM and SGAs, in addition to ETT, is an important distinguishing factor and strength of our study that may explain the difference in results.…”

“…Current evidence suggests that these are the highest yield interventions for patients in OHCA 10. If predefibrillation ETCO 2 is proposed as a marker for the optimal timing of VF defibrillation,11–14 a measure of CPR quality and patient prognostication, a more easily accessible and reliable measure is likely required. Only then will we be able to gradually move away from the current algorithmic approach to ACLS management.…”

“…One study found that in patients with ETCO 2 of <7 mm Hg (0.93 kPa), no shocks were successful at terminating VF, and in patients with ETCO 2 of >45 mm Hg (6.00 kPa), all shocks were successful 11. All four studies concluded that higher predefibrillation ETCO 2 was associated with a significantly higher likelihood of achieving ROSC, with two of the studies showing a higher likelihood of achieving ROSC only after the first defibrillation 11–14…”

“…Predefibrillation end-tidal CO 2 (ETCO 2 ) has emerged as a potential tool to guide the optimal timing of defibrillation 11–14. Several groups have studied the association between the ETCO 2 value prior to defibrillation and the likelihood of termination of VF/pulseless ventricular tachycardia (pVT) and return of spontaneous circulation (ROSC) after defibrillation.…”

Optimizing defibrillation during cardiac arrest

“…Similar to AMSA, other physiological measures have been proposed as chest compressions quality parameters during CPR [44,45], for example the end-tidal CO 2 (ETCO 2 ) [46,47]. In a retrospective analysis, both AMSA and ETCO 2 were independent predictors of shock success and ROSC [48 ▪ ]. However, AMSA was superior to ETCO 2 as a single-feature predictor of shock success and ROSC (AUC for shock success: 0.68 vs. 0.59; AUC for ROSC 0.74 vs. 0.56).…”