Accuracy of a Weight-Based Formula for Neonatal Gastric Tube Insertion Length

Gastric tubes are used in nurseries on a daily basis. Various methods of estimating gastric tube length for insertion using anatomical landmarks are used to assist correct placement. Sometimes, however, they can be up to 55% inaccurate. In 2012, we published a weight-based formula to estimate gastric tube length for insertion.

This study reviews the rates of correct gastric tube placement, as confirmed by radiography, after the incorporation of this weight-based formula into bedside practice.

A 6-month prospective study was performed in a tertiary neonatal intensive care unit. The formula estimating gastric tube length for insertion had been derived in an earlier study. This was incorporated into the hospital's policies and procedures guideline for the insertion of gastric tubes. Neonates with gastric tubes who required radiography for clinical reasons were included. The infant's weight and the type (orogastric or nasogastric) and length of tube were documented. A single radiologist assessed the tube position to be high, borderline, correct, or long.

A total of 195 chest radiographs were obtained. Correct tube position was found in 84% of instances. This was a statistically and clinically significant improvement.

Implementation of a simple weight-based estimate for gastric tube length improves correct position rates.

Further studies comparing accuracy of length/height and weight-based estimations for gastric tube insertion lengths in very preterm and extremely preterm infants are needed.