Testing Placement of Gastric Feeding Tubes in Infants

Area of Science:

• Medical Devices
• Gastroenterology
• Pediatric Critical Care

Background:

• Accurate nasogastric tube (NGT) placement is crucial in critically ill infants to prevent serious complications.
• Differentiating gastric from tracheal aspirates is essential for confirming correct NGT positioning.

Purpose of the Study:

• To compare pH cut points (< 4.0, < 4.5, < 5.0, < 5.5) for differentiating gastric and tracheal aspirates.
• To evaluate the utility of a pepsin assay in distinguishing between gastric and tracheal aspirates.

Main Methods:

• Collection of gastric and tracheal aspirates from infants on mechanical ventilation with NGTs or orogastric tubes.
• Testing aspirates using colorimetric pH indicators and a rapid pepsin assay.
• Correlation with medical record data on treatment conditions.

Main Results:

• Analysis of 212 gastric and 60 tracheal aspirates.
• A pH cut point < 5.5 showed highest sensitivity but lowest specificity.
• 100% positive predictive value was achieved at pH < 5.0, with optimal negative predictive values at this cut point.
• Pepsin assay detected pepsin in 88.3% of gastric aspirates vs. 5.4% of tracheal aspirates.

Conclusions:

• A pH cut point < 5.0 offers the best balance of positive and negative predictive values for confirming gastric aspirates, irrespective of feeding or acid inhibitor status.
• The pepsin assay is a valuable adjunct for differentiating gastric from tracheal aspirates.