What method is used as final confirmation of the proper placement of an endotracheal tube?

Choice A rationale Pulse oximetry measures the oxygen saturation in the blood and provides information on oxygen delivery, not the physical placement of the endotracheal tube. A pulse oximeter reading may be high even with an improperly placed tube if the patient is on high-flow oxygen, providing a false sense of security. It is a secondary, not a definitive, indicator of correct placement. Choice B rationale Blood gas analysis provides quantitative data on oxygenation and ventilation, but it is not a real-time, definitive confirmation of endotracheal tube placement. It takes time to get the results, and the tube could be improperly placed in the esophagus while a patient is still adequately oxygenating due to pre-oxygenation. It is a useful monitoring tool but not for initial confirmation. Choice C rationale Auscultation of bilateral breath sounds can provide presumptive evidence of proper tube placement, but it is not a definitive confirmation. Sounds can be referred from the stomach or a mainstem bronchus, leading to a false interpretation. The gold standard requires a more objective measure, such as capnography, to confirm the tube is in the trachea. Choice D rationale The detection of end-tidal CO2 via a colorimetric capnography device is considered the most reliable and definitive method for confirming endotracheal tube placement. The presence of sustained carbon dioxide in the exhaled breath indicates that the tube is in the trachea, not the esophagus. The device changes color in the presence of CO2, providing immediate visual confirmation.