AIM: To evaluate the effect of various methods of small bowel preparation on the transit time and the quality of visualization of the entire small bowel mucosa.

METHODS: Ninety-five patients underwent capsule endoscopy (CE) by easily swallowing the capsule. They were divided into three study groups according to the preparation used: group A (n = 26) by polyethylene glycol (PEG) liter or with sodium phosphate (SP) 12 h prior to the CE study; group B (n = 29) by erythromycin 1 h prior to the CE study; and group C (n = 40) without any preparation. Visualization ranged from good to satisfactory to poor.

RESULTS: The gastric emptying time in the group prepared with erythromycin was shorter but without statistical significance and the small bowel transit time was unaffected. In elderly subjects prepared by PEG or SP, the gastric emptying time was significantly longer (163.7 min, P = 0.05). The transit times of the three sub-groups were not affected by gender or pathology. The grade of cleaning of the entire study group was 3.27 ± 1.1. The erythromycin group presented significantly the worst quality of images (P = 0.05) compared to the other sub-groups. Age, gender, and pathology had no effect on the quality of the cleaning of the small bowel in the sub-groups. One (1.05%) case had no natural excretion.

CONCLUSION: Erythromycin markedly reduces gastric emptying time, but has a negative effect on the quality of the image in the small bowel. The preparation of elderly subjects with PEG or SP has a negative effect on the small bowel transit time.

The capsule endoscopy (CE) is well accepted as a tool for evaluating small bowel pathology[1-5]. However, this new technology has several limitations, i.e., the time required to study the video, it takes an hour to watch the video of the small bowel and the residual material, especially in the ileum adversely affects the image[5-7]. Stomach emptying and small bowel motility depend upon a number of factors, such as the composition of the food and fluid in the gastrointestinal (GI) tract, diseases, etc. In addition, transit time differs according to whether the individual has eaten or is in a fasting state. The initial capsule experiences showed that the cecum could not be viewed in approximately 20% of the study population because of the short battery life, because the capsule had remained in the stomach for more than 60 min[5,6] and for a variety of other reasons. A shorter transit time would be directly beneficial in obviating the first two problems.

The CE is completely different from the standard endoscopy that allows the endoscopist to remove all the residual material to improve the image. In most CE studies, the image quality in the proximal small bowel is much superior to that in the distal ileum, due to residual material.

The reasons that some physicians refuse to adopt the CE study are the time consuming viewing procedures and the frustration of being unable to view the entire small bowel because of the residual material. So far there is still no definite answer to the question of which is the best way to prepare patients for the CE study. The Given Imaging Ltd recommendation is a 12-h fast prior to the CE study with no other preparation. Most of the published studies followed this recommendation and although other methods of preparations were mentioned, no comparative study was made.

In this study, we designed to determine the best preparation to provide the most complete visualization of the entire small bowel, as well the best preparation for rapid gastric emptying times.

Ninety-five patients (55 men and 40 women, aged 18-91 years, mean age 50.1 ± 17.5 years) were enrolled in the study (Table 1). The reasons for the CE studies: iron deficiency anemia (49 patients); abdominal pain/irritable bowel syndrome (27 patients); suspected Crohn’s disease (9 patients); and miscellaneous disease (10 patients) (celiac disease, familial adenomatous polyposis, intestinal lymphoma, ulcerative colitis, Table 1).

There were pathological findings in 54 (56.8%) patients, such as angiodysplasia, ulcer, suspected Crohn’s disease, erosions, polyps, edematous mucosa, etc. In 17 cases (17.9%), the capsule failed to reach the cecum before the end of the -420 min recording time.

The mean gastric emptying time was 41.7 ± 51.5 min and the transit time of the small bowel was 225?0.6 min of the entire study group. The gastric emptying time in the group prepared with erythromycin was shorter but not statistically significant (Table 2). In elderly subjects prepared by PEG or SP, the gastric emptying time was significantly longer (163.7 min) compared to the other preparations (P = 0.05, Table 3). The small bowel transit times were similar in the three age sub-groups; however, a non-significant shorter transit time was seen in the mid-age group (41-60 years) prepared with PEG or SP (Table 3). The gender and pathology neither affected the transit time of the whole study group nor that of the three age sub-groups.

The grade of the cleaning of the entire study group was 3.27 ± 1.1, on a scale of 1 (best image) to 5 (worst, Table 4). In comparison with the other sub-groups, the erythromycin group significantly presented the worst quality of image (P = 0.05). Age, gender, and pathology had neither effect on the quality of the cleaning of the entire small bowel study group nor on the arbitrarily selected three age sub-groups (Table 4).

The capsule passed through without difficulty in all cases except for one (1.05%) patient who had no natural excretion, and was found to have Meckel’s diverticulum (the Meckel scan that was done prior to the CE study was interpreted as normal).

The average amount of time needed for an expert to review one video was about 50 min.

The Given^® Diagnostic Imaging System M2ATM Capsule is a new system designed to aid the gastroenterologist in diagnosing small bowel diseases[5,7-9].

The ingestible capsule records video images during natural propulsion through the digestive system. Averages of 50 000 images are obtained during the 8-h passage of the capsule. The CE is propelled by peristalsis through the intestinal tract and permits direct viewing of the entire small intestine[2-5]. From the initial capsule experience, we learned that in approximately 20% of the study population, the capsule did not reach the cecum (the view not the capsule) for several reasons: short battery life (7 ± 1 h); the capsule remaining in the stomach for more than 60 min; and as well the quality of the image, especially in the distal part of the ileum. Practical experience has shown that visualization of the entire small bowel mucosa may sometimes be hindered by the presence of residual material. For these reasons, in some of the CE studies, it was impossible to visualize the entire small bowel[5-7].

More than 180 000 patients worldwide have swallowed the CE. It is estimated that 19 million people in the USA alone may suffer from diseases related to the small intestine, including obscure bleeding, irritable bowel syndrome, Crohn’s disease, chronic diarrhea, and cancer. Hence, these will expand the need for CE, and endoscopy services are under increasing strain and to read one CE study takes approximately 1 h of the very expensive time of an expert endoscopist. This could well be the reason that some physicians refuse to adopt the CE study[5-9]. CE is a diagnostic tool with enormous potential and our expectations are that it will yield answers that other procedures are not capable of providing, and with time demand for CE, studies will grow.

There is a lack of data of the effect of colonic preparation on the stomach and the small bowel. Recently, Basit et al[10] have demonstrated that PEG 400 has a marked accelerating effect on small intestinal liquid transit, which, in turn, has implications with PEG 400. In addition, SP effectively shortens small bowel transit time[11]. On the other hand, Sood et al[12] found no significant difference in the mean transit time in the stomach, duodenum, and small bowel between PEG 400 and plain water. The macrolide antibiotic erythromycin has been known to be associated with increased GI motility because of its introduction more than 35 years ago and evidence for its therapeutic efficacy in gastroparesis[13,14]. However, regarding the effect of erythromycin on the transit time of small bowel and its cleaning effect, we have no data. At present, the two major requisites are image quality improvement and reduction of the time spent in viewing the CE videos.

As shown by our study, the gender and the presence of pathology lesions had no impact on the cleaning and transit time. Preparation with erythromycin reduced the transit time in the stomach (especially in 40-60-year-old age group), but had a negative effect on the quality of the image in the small bowel. In elderly patients, small bowel transit time and gastric emptying time were significantly longer in those prepared with PEG or SP when compared to the other preparations (P = 0.05), but with no effect on the quality of the image.

To the best of our knowledge, this is the first time a study tried to deal with the problems of image quality improvement and reduction of CE viewing time through evaluation of various preparation techniques. After testing the various preparations, we had to concede that they neither offered any improvement in the time needed to read the study nor in image quality over the 12-h fasting period as recommended by the Given Company. Even though erythromycin has the best effect on gastric emptying time, the quality of the view in the small bowel is the worst, for which we have no explanation and preparation with PEG or SP has a negative effect on the transit time of the small bowel. We need other pharmaceutical tools and/or technical aid to improve the time and the quality of the CE study.

The authors thank Carmela Reisler and Esther Eshkol for editorial assistance.