Background Capsule endoscopy, as a non-invasive diagnostic tool for the gastrointestinal tract, heavily relies on the cleanliness of the stomach. Traditional bowel preparation methods may face challenges such as poor patient compliance and inconsistent efficacy. Sodium bicarbonate, functioning as an antacid, neutralizes gastric acid, reducing the acidic environment in the stomach, thereby enhancing gastric cleanliness during capsule endoscopy and providing a clearer field of view. This study aims to evaluate the efficacy and safety of orally administered sodium bicarbonate injection solution as a novel gastric cleansing regimen in improving intragastric cleanliness for capsule endoscopy.

Methods A randomized controlled clinical trial was conducted involving 200 patients who underwent capsule endoscopy, randomly allocated into experimental (n=100) and control (n=100) groups. The experimental group, after standard gastrointestinal preparation, orally consumed warm water to a sense of fullness, followed by 100ml of isotonic sodium bicarbonate injection solution before swallowing the capsule for the examination. The control group underwent routine oral intake of warm water until fullness without the sodium bicarbonate solution before capsule ingestion. Gastric cleanliness was assessed via direct observation of the gastric mucosa under capsule endoscopy, with evaluation criteria encompassing residual substances, mucus coverage, and turbidity of gastric fluids. A standardized scoring system across six gastric regions (cardia, fundus, body, angular notch, antrum, and pylorus) was applied, assigning scores from 1 (severely unclean with substantial obstructions) to 4 (virtually pristine with an unobstructed view). Any adverse reactions were documented throughout the process.

Results The results demonstrated significantly better gastric cleanliness in the experimental group compared to the control group (mean cleanliness score: 3.2±0.6 vs. 2.6±0.7, P<0.001), particularly in reducing mucus, gas bubbles, and fluid turbidity, highlighting a distinct advantage for the experimental group. Moreover, no severe adverse events were reported in either group, confirming the safety and feasibility of this approach.

Conclusions Oral administration of sodium bicarbonate injection solution is an efficacious and safe gastric cleansing strategy that markedly enhances visual clarity within the stomach during capsule endoscopy, facilitating improved diagnostic accuracy. This finding introduces a new preparatory strategy for optimizing pre-endoscopic procedures.