Ongoing Nasogastric Tube Verification: The Evidence

The ongoing verification of Nasogastric Tube location presents a challenging clinical dilemma and the risk to the patient of incorrect placement is grave.  Current practice demonstrates almost universal continuance of practices that have been demonstrated to be unsafe.  Chief among these would be the continued use of auscultation as a verification strategy. The purpose of this project was to examine the body of evidence using a structured Evidence-Based Practice (EBP) process to determine research based strategies.  The background search resulted in consistent recommendation for the use of X-ray for initial verification. In addition, this phase of the search also resulted in a recommendation regarding proper measurement of the tube length prior to insertion. These recommendations will be included with the recommendations made regarding ongoing verification. The evidence was searched using a PICO question: “In patients with NG tubes, how does pH testing of gastric aspirate affect verification of correct tube placement?”  The choice of the pH technique was selected based upon its consistent representation in the body of available evidence. Appraised evidence included primarily Level IV studies and Level VII expert opinion.  This issue appeared to have been intensively studied in the late 1990’s and early 2000’s, and therefore some of the selected evidence exceeds ten years. After synthesis of the evidence, six recommendations for practice were made related to initial placement technique, initial X-ray verification and ongoing verification.  The primary recommendation that would improve practice is the need to do pH testing of aspirate and one additional verification strategy every time the tube is accessed for care.  Current practice is auscultation of an air bolus, which the evidence supports as being unreliable and unsafe. This project, if disseminated, has the potential to improve patient safety by reducing the risk of untoward events related to displacement of the tube. The investigation indicates that more research is needed in identifying a consistently safe and reliable method for ongoing bedside verification of nasogastric tube placement.