In this study, we found no association between use of antispasmodics and rates of detection of targeted lesions by screening endoscopy. Examining the usefulness of antispasmodics in EGDS is important because they can have adverse events 14,15, and most screening EGDS take less than 10 minutes 7. In the present study, we found that using antispasmodics conferred no benefits regarding detection of suspicious lesions.
Few studies have been published on factors associated with detection of lesions by screening EGDS. Omata et. al. reported finding no statistically significant differences in rates of detection of upper gastrointestinal neoplasia according to the experience of the endoscopist 12. As shown in Table 2 shows, we also found no association between detection rate and endoscopists’ experience. Indeed, we did not identify any clinical factors that significantly impacted the rate of detection of lesions by screening EGDS.
Peristalsis is visible in the upper gastrointestinal tract, especially the esophagus, gastric antrum and second part of the duodenum, making examination of these regions so difficult that lesions can be missed. However, our subgroup analysis (Table 3) showed no significant differences between the antispasmodic and non-antispasmodic groups in the location of tumors detected in the esophagus, stomach or duodenum. These findings suggest that antispasmodic use confers no advantages regarding detection of lesions, not even affecting the rate of missing lesions in regions with active peristalsis.
The Handbook for screening EGDS published by the Japan Gastroenterological Endoscopy Society 16 does not recommend routine use of scopolamine or glucagon because there is no good evidence that these agents confer any benefit regarding detection of lesions and they can have adverse events 7 17–23. However, L-menthol is reportedly safe 8. Furthermore, our subgroup analysis (Table 4) showed a slightly higher, but not statistically significant (P=0.07), rate of detection in the L-menthol than the scopolamine group. These findings suggest that L-menthol may be a better option than scopolamine when suppression of peristalsis is required.
The expected advantages of not using antispasmodics are as follows. First, this would eliminate the risk of associated adverse events. Scopolamine is associated with cardiovascular events 7,17 and tachycardia and can also adversely affect the ocular, urinary and salivary systems 7. Additionally, it can cause allergic reactions 18,19, including potentially fatal anaphylactic shock 20. Glucagon can lead to delayed hypoglycemia7,17 and induce nausea, vomiting and anaphylactic and other allergic reactions21 22,23. Second, not using antispasmodics would eliminate their cost. One ampoule of scopolamine, glucagon and L-menthol costs 12.7, 30 and 7 USD, respectively. From October 2015 to September 2020, our hospital spent a mean of 43228 USD per year on antispasmodics. Third, participants would not be subjected to the pain of an intramuscular injection of scopolamine or glucagon. Fourth, not using antispasmodics would mean one less task for nurses. Eliminating the need for nurses to open an ampoule and inject an antispasmodic would free them up to attend to their many other tasks, such as monitoring participants, recording and preparing other agents. Moreover, it would reduce their exposure to the risk of needle-stick injury.
Our study had several limitations. First, it was an observational study. Undetected differences in the characteristics of the antispasmodic and non-antispasmodic groups may have caused biases despite the use of multivariate analysis. Second, the generalizability of our findings is limited because this was a single hospital study. Third, there were too few participants to analyze our findings by organ. Fourth, we did not evaluate several subjective factors, namely the stress for endoscopists on encountering peristalsis in the upper gastrointestinal tract and the participants' tolerance of the EGDS procedure.
In conclusion, premedication with antispasmodics (scopolamine, glucagon and L-menthol) does not improve the rate of detection of lesions by screening EGDS.