The nurse inserts a small-bore nasoduodenal tube for a patient who is undernourished. What priority nursing action is required prior to starting the continuous tube feeding to confirm correct tube placement?

Choice A rationale The gold standard for confirming the correct placement of a nasoduodenal tube is a chest or abdominal x-ray. This is a priority action because it provides a definitive visual confirmation of the tube's location, ensuring it is not misplaced in the trachea or bronchi, which could lead to fatal aspiration of the feeding. Choice B rationale Assessing for carbon dioxide using capnometry is a method used to detect tracheal placement of an endotracheal tube. While a positive reading indicates respiratory placement, a negative reading does not definitively confirm gastrointestinal placement of a small-bore tube. Aspiration of gastric contents and other factors can produce false negatives. Choice C rationale Auscultating for a rush of air over the epigastric area after injecting air is an unreliable method for confirming nasoduodenal tube placement. The sound can be misleading and does not guarantee the tube is not in the lungs, as the sounds can be transmitted from the esophagus or trachea, leading to a false sense of security. Choice D rationale Performing a pH test of gastric fluid can indicate placement in the stomach if the pH is acidic (typically 1-5). However, it does not confirm duodenal placement and can be unreliable if the patient is on acid-suppressing medication. A pH greater than 6 could indicate placement in the lungs or intestines.