AACN Essentials Of Critical Care Nursing Practice Test

Using capnography to confirm airway placement and monitor ventilation. An end-tidal CO2 detector measures the CO2 level in exhaled air and provides a waveform that shows CO2 is being delivered from the lungs. After securing the airway, a consistent end-tidal CO2 waveform with normal values confirms tracheal placement and effective ventilation. If CO2 is not detected or the waveform is absent, it raises concern for esophageal intubation or tube dislodgement, prompting immediate reassessment and repositioning. Capnography also helps track ventilation efficiency over time by showing trends in CO2 elimination; rising CO2 can indicate hypoventilation or rebreathing, while very low CO2 may reflect hyperventilation or poor perfusion. In contrast, a pulse oximeter only shows oxygen saturation and does not verify placement or provide immediate ventilation data, a thermometer is unrelated, and a stethoscope alone cannot reliably confirm airway placement or quantify ventilation.