Yilmaz G, et al. - Researchers here performed a comparison of the carotid blood flow measurement with end-tidal carbon dioxide (ETCO2) measurement and evaluated whether this method could be used as an alternative method to capnography in the assessment of cardiopulmonary resuscitation (CPR) efficacy. Observations revealed a low correlation between the PSV and ETCO2 values. With effective CPR, they obtained results close to carotid blood flow in normal healthy individuals. However, carotid blood flow measurement results during CPR were not as valuable as ETCO2 in expressing CPR efficacy.