A nurse is preparing to administer an enteral feeding via NG tube for a client the day after verifying placement of the tube using a chest x-ray. Which of the following methods should the nurse use to confirm placement prior to initiating the feeding?

A. Test the glucose level of the client's pulmonary secretions: Testing glucose in pulmonary secretions is not a reliable method for verifying NG tube placement. Pulmonary secretions may have variable glucose levels and cannot confirm gastric placement, making this method unsafe for ensuring the tube is correctly positioned. B. Ask the client to speak after air instillation: Having the client speak after air instillation is not a valid or safe method to confirm NG tube placement. Speaking does not provide any reliable indication of whether the tube is in the stomach or lungs and could lead to a false sense of security. C. Auscultate the client's stomach during air instillation: Listening for a “whoosh” of air over the stomach has been a traditional practice but is unreliable and not recommended as the sole method. Air may also enter the lungs, producing a similar sound and potentially causing harm if feeding is initiated in a malpositioned tube. D. Test the pH level of the client's gastric aspirate: Measuring the pH of aspirated gastric contents is a safe and effective method to confirm NG tube placement. Gastric fluid typically has a pH of 1–5, whereas respiratory secretions are more alkaline. This provides reliable verification before initiating enteral feeding.