SESSION TITLE: Imaging Posters
SESSION TYPE: Original Investigation Poster
PRESENTED ON: Wednesday, October 28, 2015 at 01:30 PM - 02:30 PM
PURPOSE: The nasogastric (NGT) and orogastric tube (OGT) are essential inpatient tools. To confirm placement Chest X-Ray (CXR) is preferred, but may represent over-use of time and resources. We have developed a simple ultrasound (US) protocol for the bedside confirmation of feeding tube placement, which is rapid, cost effective, decreases exposure to radiation, requires little experience and is easy to replicate without adding any substances. Prior ultrasound studies relied on direct visualization of the NGT/OGT tip in the stomach or administration of fluid through the gastric tube whereas our protocol is unique and more reliable.
METHODS: US involved two criteria. First, the anterlateral neck was scanned in high frequency to visualize the gastric tube’s characteristic echogenic surface with posterior anechoic shadow in the esophagus. Then, the right diaphragm location was identified by low frequency imaging. A distance was measured from the diaphragm to the temporomandibular joint (TMJ), then TMJ to the nose or mouth (for NGT or OGT, respectively). To be well positioned, their sum would be less than the marking on the tube at the mouth or nose. Comparisons of US findings were then made to the CXR findings. Data was collected by a single internal medicine resident. All statistical analyses were performed by the Biostatistical Consulting Core.
RESULTS: 32 patients were studied. The gastric tubes were confirmed to be in the esophagus and below the diaphragm in 28 cases. In two cases, the ultrasound scan falsely predicted the tubes to be incorrectly positioned. While in two cases, the tubes were not correctly inserted and the ultrasound yielded a true negative result. The sensitivity of ultrasound was 93% (79.5%-98.8%), specificity was 100% (22.4%-100%), positive predictive value (PPV) was 100% (9.8-90.2%), while the negative predictive value (NPV) was 50% (89.1%-100%). The length of the gastric tube protruding below the diaphragm estimated by ultrasound was within 2.74 cm (SD 2.34cm) of the CXR measurement.
CONCLUSIONS: We have demonstrated a novel and reliable approach for confirming placement of NGT/OGT using ultrasound in the hands of a physician with limited training and without prematurely pushing fluid. Our method maintained a strong positive predictive value and accurately estimated the projected length below the diaphragm when compared to CXR.
CLINICAL IMPLICATIONS: Our method should be considered an adjunct or alternative to CXR for NGT/OGT placement with the aim of saving cost, radiation exposure, and resources.
DISCLOSURE: The following authors have nothing to disclose: Vlad Radulescu, Sahar Ahmad
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