Capnometry and Air Insufflation for Assessing Initial Placement of Gastric Tubes

Abstract

BACKGROUND: Nurses are often responsible for placement of large-bore gastric tubes. Tube misplacement into the lungs is a potential complication with serious sequelae. The reliability of common bedside methods for differentiating between pulmonary and gastric placement has not been acceptable. OBJECTIVE: To compare the accuracy of capnometry (colorimetric indicator of end-tidal carbon dioxide) and air insufflation/auscultation with the accuracy of radiography in detecting the location of gastric tubes. METHODS: A prospective convenience sample of insertions of Salem sump gastric tubes was studied. Tubes were inserted by nurses according to the unit's standard procedure, and air insufflation/auscultation, capnometry, and radiography were used to detect the position of the tubes. Results obtained with each of the methods were compared. RESULTS: A total of 91 tube placements were studied in 69 patients. No radiographically documented instances of lung placement occurred. Capnometry incorrectly indicated 15 of 91 gastric placements (16%) as placements in the lung. Air insufflation/auscultation incorrectly indicated 5 of 91 gastric placements (5%) as placements in the lung. CONCLUSIONS: Neither air insufflation nor capnometry is a fail-safe method for determining placement of gastric tubes. Radiography remains the preferred method.