A ventilation analysis system comprising an interface module adapted to receive a carbon dioxide (CO2) signal and a breath flow dynamics signal, and control logic adapted to produce a ventilation indicator, based on a mutual analysis of the CO2 signal and the breath flow dynamics signal. The ventilation indicator may be, for example, an estimated CO2 waveform, an End-Tidal CO2 (ETCO2) value, and/or a minute CO2 value.