Pediatrics
Pediatric orogastric and nasogastric tubes: A new formula evaluated*,**

Presented in part at the North American Congress of Clinical Toxicology, La Jolla, CA, September 1999; and the American Academy of Pediatrics, Section of Emergency Medicine, Washington, DC, October 1999.
https://doi.org/10.1067/mem.2002.120124Get rights and content

Abstract

Study Objective: We sought to compare the traditional method of determining depth of gastric tube insertion, by measuring from the external landmarks of the nose or mouth, to the earlobe, to the xiphoid process (NEX method), with a graph for determining depth of gastric tube insertion that is based on patient height (graphic method). Methods: A prospective, randomized, double-blinded study comparing NEX and graphic methods for gastric tube depth of insertion was undertaken. This study included a convenience sample of pediatric emergency department patients in need of gastric intubation. Patients were block randomized, and their gastric tubes were placed to the depth derived from the particular method employed. Alternate depth of insertion was measured on all patients. Abdominal radiographs were used to determine the distance that the end of the tube was from the center of the stomach. Results: Forty-four patients each were in the NEX and graphic groups. The mean distance from the center of the stomach was −1.12 cm (SD 1.36) for the graphic group, compared with 1.31 cm (SD 3.39) for the NEX method. The difference between the 2 methods was 2.43 cm (95% confidence interval [CI] 1.33 to 3.54). Using absolute values, the mean distance from the center of the stomach was 1.26 cm (SD 1.23) for the graphic group compared with 2.60 cm (SD 2.51) for the NEX method. Using these values, the difference between the groups is 1.34 cm (95% CI 0.50 to 2.18). Conclusion: When compared with the NEX method, the graphic method demonstrates a significant ability to more consistently and accurately determine the depth of pediatric gastric tube insertion. [Klasner AE, Luke DA, Scalzo AJ. Pediatric orogastric and nasogastric tubes: a new formula evaluated. Ann Emerg Med. March 2002;39:268-272.]

Introduction

Gastric tubes (oral and nasal) are needed in the pediatric setting for a number of reasons, including decompression of bowel obstructions; contrast placement in traumatized, incoherent, uncooperative, or very young patients; and lavage and/or instillation of activated charcoal after acute ingestions from toxic substances. The placement procedure for gastric tubes, known as the NEX method, has traditionally been based on the estimation from the nose or mouth to the earlobe, to a point midway between the xiphoid process and umbilicus, with gastric auscultation for confirmation.1

This method for determining depth of gastric tube placement had been used for many years without challenge. In 1992, Scalzo et al,2 after review of 36 pediatric patients needing gastric tubes, reported a 50% (7/14) malposition rate according to a radiograph after the NEX method had been used to estimate tube depth. Scalzo et al suggested that a tube insertion formula derived from Strobel et al's3 previously published formula for esophageal pH probe placement, which was determined on the basis of the patient's height, might be a more consistent method of determining tube depth of insertion.2 Strobel et al's original formula included lengths for both oral and nasal insertion as follows:Nasal Insertion: Esophageal Length (cm) = 6.7 + [0.226 × Height (cm)]Oral Insertion: Esophageal Length (cm) = 5.0 + [0.252 × Height (cm)]

Scalzo et al2 modified the formula, using a correction factor to account for the confines of the more distal insertion of tubes into the stomach. This modified formula, determined on the basis of height, was displayed in graphic form and is known as the graphic method (Figure 1).Scalzo et al proceeded to use this formula/graph on 6 pediatric patients and demonstrated correct placement in 100% of these patients, based on follow-up radiographs. This study served to evaluate the accuracy of depth of gastric tube insertion using this graph. We conducted a double-blinded, randomized, controlled trial to test the hypothesis that the graphic method resulted in comparable or better accuracy in depth of tube determination compared with the traditional NEX method.

Section snippets

Materials and methods

This study was a prospective, double-blinded, randomized clinical trial that enrolled a convenience sample of 89 children who presented to a university-affiliated children's hospital from May 1, 1996, to May 31, 1998. The study design and patient consent procedures were approved by the institutional review board.

Children were eligible if they were between the ages of 6 months and 18 years and in need of a gastric intubation in the emergency department. Informed consent was obtained from the

Results

Eighty-nine patients were prospectively enrolled. Forty-four patients were randomly assigned to the NEX method, and 45 patients were assigned to the graphic method. One patient in the graphic group was excluded because the radiographs were unreadable as a result of poor penetration, making measurements unobtainable. This left 88 patients for analysis, with 44 in the NEX group and 44 in the graphic group.

The demographics for the 2 groups, including age, height, weight, percentile height for age,

Discussion

This study illustrates the dramatic variability that can occur with gastric tube placement. The NEX method demonstrated a greater mean distance off from the center of the stomach, with nearly twice as much variability compared with the graphic method (1.31 cm [SD 3.39] versus −1.12 cm [SD 1.36]). Examination of the box plots in Figure 2 reveals an important characteristic of tube insertion using the graphic method. Both the NEX and the graphic methods result in tube placement that on average is

Acknowledgements

Author contributions: AEK and AJS conceived the study and designed the trial. AEK acquired the data. DAL provided statistical advice on study design and analyzed the data. AEK drafted the manuscript, and all authors contributed substantially to its revision. AEK takes responsibility for the paper as a whole.

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*

Author contributions are provided at the end of this article.

**

Address for reprints: Ann E. Klasner, MD, MPH, 1600 7th Avenue South, Midtown Center, Suite 205, Birmingham, AL 35233; 205-934-2116, fax 205-975-4623; E-mail: [email protected]

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