Controlled comparison of traditional feeding tube verification methods to a bedside, electromagnetic technique

Background. Benefits of enteral feeding are diminished by aspiration pneumonia and mechanical complications of misplaced feeding tubes. To avoid complications, clinicians determine the location of the tip before feeding. This study compares diagnostic test characteristics of 4 techniques for tip localization. Methods: A prospective, blinded trial was conducted on the wards and critical care units of four acute-care hospitals. Patients requiring at least 3 days of enteral feeding were studied. Four observers at each institution used a randomly assigned technique to determine a tube's tip location. Methods included auscultation, aspiration with, inspection or pH determination of aspirated material, and a recently developed electromagnetic technique. Results were compared with radiographic determination. Success rates were compared using sensitivity, specificity, and likelihood ratios. Results: The 4 methods agreed with the radiograph in (mean, 95% confidence interval): 84 (80 to 88)%, 50 (45 to 55)%, 56 (51 to 61)%, and 76 (72 to 81)% of observations, respectively. Only the electromagnetic method and aspiration identified all tubes located above the diaphragm (negative likelihood ratio 0 and sensitivity 100%). Aspiration was unsuccessful in making a determination in 53% of the observations, whereas the electromagnetic method was successful 90% of the time.