pH and Concentration of Bilirubin in Feeding Tube Aspirates As Predictors of Tube Placement

Abstract

Preliminary laboratory-based data indicate that appropriate use of the proposed algorithm could significantly reduce the number of x-rays needed to exclude respiratory placement and to distinguish between gastric and intestinal placement.

Examining the Evidence to Guide Practice: Challenging Practice Habits

“…Aspirates with bilirubin levels of 5 mg/dL or greater, pepsin levels less than 100 μg/mL, and trypsin levels greater than 30 μg/mL have been associated with intestinal placement in adults. 122,123 Although some researchers have reported similar results in neonates and children for bilirubin, 124,125 others have failed to find a bilirubin concentration of 5 mg/dL or greater to be predictive of tubes placed in the duodenum. 89 Bilirubin may be helpful to identify postpyloric placement; however, bilirubin results, on their own, do not enable discrimination between esophageal, gastric, and respiratory placement of feeding tubes.…”

“…Aspirate pH is helpful in determining gastric placement, but results are not always useful for distinguishing between respiratory and intestinal fluids, because both are alkaline. 122,133 Because a variety of situations may affect gastric pH in infants and children, including administration of total parenteral nutrition, 134,135 fasting versus feeding, 122 and…”

Feeding Tube Placement in Adults: Safe Verification Method For Blindly Inserted Tubes

“…1,2,4,8,[12][13][14][15][16][17][18][19] A variety of methods were used to evaluate tube placement: 7 studies evaluated pH, 3 used capnography/capnometry, 3 used auscultation, 2 measured bilirubin levels, 1 measured enzyme levels, and 1 used visual inspection. Five of the 12 studies used multiple methods.…”

“…Additionally, although bilirubin/enzyme testing shows promising results, these methods are not available for use at the bedside. [15][16][17] Three practices that have been used for tube verification-auscultation, aspirate inspection, and placing tubes underwater to assess for "bubbling"-should be discontinued because of their lack of established efficacy and potential risk for harm. Of concern, an audible "air pop" over the epigastrum falsely leads clinicians to assume correct gastric placement of a aspirate could be gastric reflux.…”

“…15 On their own, bilirubin results can be misleading, because levels less than 5 mg/dL could indicate gastric/pulmonary placement; however, a combination of a pH greater than 5 and a bilirubin level less than 5 mg/dL typically indicates pulmonary placement. 16,17 Similar to other verification methods, these tests may help to www.ajcconline.org Interventions with no evidence of any benefit; often some evidence of harm feeding tube. Hospital policies should be revised to reflect evidence-based practices.…”