Variability in Gastric Emptying Meals Used in Clinical Practice...Seriously?

Objectives Gastric emptying scintigraphy (GES) is used to measure gastric motility in patients with symptoms suggesting altered gastric emptying or motility. The composition of the solid meal for GES significantly affects the emptying rate. Solid components empty more quickly than liquid. Fats empty more slowly than proteins or carbohydrates. The caloric content and volume also affect gastric emptying. Lack of uniformity of the test meal affects valid comparisons to normal values and, thus, may alter the interpretation of normal versus delayed emptying.1 To address this problem, SNMMI published Procedure Guideline for Adult Solid-Meal Gastric-Emptying Study 3.0 in 2009.2 This recommends a validated, standardized low fat low calorie meal3. Adherence to these guidelines has not been nationally assessed. The aim of our study was to measure the rate of compliance with the standardized GES meal in a large cohort of laboratories from different institutions and practice settings across the United States.

Methods We performed a retrospective study of all laboratories applying for Intersocietal Accreditation Commission (IAC) general nuclear medicine accreditation from 2013 to 2015. We used the IAC database to extract GES protocols and specific details of the meals used. Both the components and preparation of the meal were evaluated. Compliant meals exactly matched the GES guideline standardized meal, consisting of 0.5 - 1.0 mCi (18.5 - 37 mSv) technetium-99m sulfur colloid scrambled with 120 gm liquid egg white (Egg Beaters® or generic) plus 2 slices of white toast, 30 gm strawberry jelly, and 120 ml water.2 The total meal energy is 255 kcal. We grouped the study meals’ composition into the following 8 categories: consensus meal; egg white partial (only some of the standard ingredients included); egg white plus (additional non-standard ingredients added, e.g. butter or juice); whole eggs meal (whole eggs substituted for egg whites in the consensus meal); whole eggs partial; whole eggs plus; oatmeal and other.

Results A total of 186 laboratories applied for general nuclear medicine accreditation during the three-year period. Of these, we evaluated gastric emptying protocols from 129 laboratories. Only 31% of meals were fully compliant with the SNMMI guideline (Table 1). Variations of the egg white consensus meal with partial or additional ingredients were used in 5% of laboratories. A majority of laboratories (47%) used whole eggs instead of egg whites with either partial or additional ingredients. Oatmeal alone or combined with additional ingredients was used in 12% of laboratories. The “Other” group (5%) used highly unusual GES meals. These included a honey bun, corn flakes and milk, peanut butter sandwich, egg salad sandwich, egg burrito, or McDonalds Egg McMuffin®. In addition we found a variety of nonconforming meal preparation methods. For instance, several facilities instructed the patient to bring their own scrambled eggs or added the tracer to already cooked eggs.

Conclusions A majority of laboratories applying for IAC accreditation are not compliant with the standardized meal as described in the SNMMI GES guideline. Laboratories most frequently substituted whole eggs instead of egg whites. Generally, normal values and performance characteristics are not available for protocols using nonconforming meals, which may result in inaccurate interpretation and affect patient management. Although SNMMI published the GES procedure guidelines >6 years ago, the results of our study demonstrate a continued gap between guideline publication and its implementation. Further dissemination and education efforts will be needed to increase utilization. $$graphic_E75372B5-67C3-4D12-8A58-FC67D8A91934$$

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