Saint Louis University

Inventor: Dr. Norma Metheny, Lisa Reed Smith and Barbara Stewart


Reliable exclusion of respiratory placement is imperative before nutrients are administered to a patient through a nasally inserted feeding tube. After excluding respiratory misplacement the clinician often finds, particularly in patients who are at high risk for pulmonary aspiration, that it is also useful to be able to clearly differentiate between gastric and intestinal feeding tube placement. Currently, radiological confirmation of feeding tube position is the "gold standard".

However, the availability of a rapid, reliable method for accurately determining feeding tube positioning that can be carried out at the patient's bedside, would reduce the number of x-ray exposures received by the patient receives and decrease treatment costs. Because gastric fluid is typically acidic, determining the pH of feeding tube aspirates can help to differentiate between gastric and respiratory as well as gastric and intestinal tube positions.

The pH value of aspirate alone, however, is not a sufficiently accurate predictor of proper feeding tube placement. In contrast a combination assay format which permits the simultaneous measurement at the bedside of pH and concentrations of bilirubin, pepsin, and trypsin in a pre-nutrient administration aspirate sample, can be used to rapidly and accurately determine whether a feeding tube is positioned within a patient's respiratory system, stomach, or small bowel.


A combination diagnostic test method which permits the rapid and accurate bedside determination of the placement of a feeding tube in the respiratory tract, stomach, or small intestine of a patient.

Category: Clinical Diagnostic Method

Keywords: feeding tube placement, aspirate, diagnostic method

Patent: US Patent 5,891,054 (Date of Patent: Apr. 6, 1999)

License: Available

Reference Number: SLU-1012

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