READING THE W AVEFORM PHASE I: Respiratory Baseline, CO2 free dead space air, normally 0 Ⅰ相: 吸气基线,应处于零位,是呼气的开始部分为呼吸道内死腔气
PHASE II: Expiratory Upstroke, rapid rise due to mixing of dead space air and alveolar air, should be steep
Ⅱ相:呼气上升支,较陡直,为肺泡和无效腔的混合气
PHASE III: Expiratory Plateau, exhalation of mostly alveolar air ☼: Peak Et CO2 Level , end of exhaled air, peak end tidal CO2 level, normally 35-45mmHg Ⅲ相::二氧化碳曲线是水平或微向上倾斜,称呼气平台,为混合肺泡气,平台终点为呼气末气流,为 PETCO2 值
PHASE IV: Inspiratory Downstroke , inhalation of CO2 free gas, quickly returns to the baseline
IV 相:吸气下降支,二氧化碳曲线迅速而陡直下降至基线新鲜气体进入气道
Hyperventilation (过度通气) In hyperventilation, the capnograph starts normal but as the rate becomes faster the waveforms become closer together and the level of end tidal CO2 be