Inspiratory end-tidal oxygen content difference: a sensitive indicator of hypoventilation.

摘要: The effect of progressive hypoventilation on end-tidal gas concentrations and corresponding partial pressures in arterial blood was studied anesthetized pigs. Oxygen, CO2, nitrous oxide were measured continuously with fast infrared paramagnetic sensors as ventilation decreased gradually 12.5% increments at 5-min intervals. Samples for determinations obtained 3 min after each respirator adjustment. An increasing difference between inspiratory oxygen (FIO2 — PetO2) the most sensitive indicator exceeded sensitivity CO2. Decreasing PetO2 followed by a decrease PaO2, but no detectable change saturation until to 37% initial value. rapidly decreasing alveolar replaced oxide, sudden drop characterized values all three gases peaked waveforms. Thus, FiO2 are valuable indicators adequate appropriate supply.