According to this study:
* Standard predictors of the internal distance to the stomach that are used for placing orogastric and nasogastric tubes in children are often inaccurate.
* Feeding tube placement should be based on age-specific equations that incorporate children's height.
Several predictor equations have been developed to assist with positioning orogastric or nasogastric feeding tubes in children when radiographic images are not available. However, the accuracy of these equations hasn't been adequately studied.
Researchers compared the actual internal distance to the stomach measured during manometry or endoscopy with that calculated using the most commonly used predictor equations. These equations used, for example, height, the distance from the tip of the nose to the upper edge of the umbilicus, or the distance from the tip of the nose to the midpoint between the xiphoid process and the upper edge of the umbilicus. The most commonly used equation, which employs the distance from the tip of the nose to the inferior attachment of the ear lobe to the tip of the xiphoid process, was also tested.
Endoscopic or manometric data obtained from 1991 to 1998 and in 2005 on 498 children ranging in age from two weeks to 19 years were evaluated. "The data showed that the relationship between esophageal length and height changed with age," said lead author Jan Beckstrand in an interview.
The predictor equations studied were found to often result in tubes being positioned above or below the body of the stomach. The nose-ear-xiphoid predictor, which is the one most often used clinically, has an overall risk of 48% of placing the tube too high. However, an age-specific predictor based on precisely measured height predicted the distance to the stomach in 98.8% of children ages 0.5 to 100 months and in 96.5% of children older than 100 months.
According to the authors, height must be precisely measured, using a calibrated stadiometer or neonatometer, with the child standing or lying without shoes and with "the head positioned so that the outer canthus of the eye is in the plane of the tragus of the ear." Ideally, two raters should each measure the child, and the calculations should be carefully verified.
"Placing and maintaining nasogastric and orogastric tubes is more complex than most nurses realize," Beckstrand said. The authors urge the use of age-specific predictor equations immediately.