Article Text


Endoscopy II
PTU-205 Pre-medication with N-acetylcysteine and simethicone improves mucosal visualisation during gastroscopy. A randomised, controlled, endoscopist-blinded study
  1. J Neale,
  2. S James,
  3. P Patel
  1. Gastroenterology, Southampton Hospitals NHS Trust, Southampton, UK


Introduction The detection of early cancer during gastroscopy in the western world is poor. UK studies have demonstrated up to a 15% miss rate during diagnostic gastroscopy for early neoplasia. Early gastric cancer has a vastly superior survival rate and may be amenable to endoscopic resection. Diagnostic gastroscopy provides a unique opportunity to diagnose early gastric neoplasia, whatever the indication; however intraluminal mucus and saliva can obscure mucosal visualisation and potential detection of these lesions. The aim of this study was to investigate whether the use of a premedication solution containing the mucolytic agent N-acetylcysteine and the surfactant simethicone improves mucosal visualisation within an unselected UK diagnostic gastroscopy service.

Methods 75 consecutive patients were recruited from a single endoscopist's diagnostic gastroscopy list. These were randomised into three groups. 1: Standard control—clear fluids only for 6 h, NBM for 2 h. 2: Placebo control – standard control + 100 ml sterile water (given 20–30 min prior to gastroscopy). 3: Solution – standard control + 100 ml investigated solution (20–30 min prior). The endoscopist was blinded to patient preparation. Inadequate mucosal visualisation was measured by assessing fluid/mucus during gastroscopy that could not be suctioned and required flushing with water. The volume of flush, the site at which it was used and the procedure time were recorded.

Results All three groups showed no statistical difference for age, gender, priority or indication. The mean volume of flush required to obtain clear mucosa was significantly less in the solution group (12.1 ml (3.5–20.7)) compared to the standard control group (54.2 ml (39.2–69.2), p<0.00003) and the placebo control group (61.0 ml (44.6–77.4), p<0.00001). This significant difference was identified across all sites recorded in the upper GI tract, bar the OGJ where very little stubborn mucus was identified in all three groups. 61% of the solution group required no flushing at all, significantly more than the standard control group (13%, p<0.002) and the placebo control group (9%, p<0.0005). Mean procedure time was less in the solution group (8.5 min (7.1–9.9)) compared with the standard control (10.4 min (8.5–12.3), p<0.075) and placebo control groups (10.5 min (9.3–11.7), p<0.028). When patients on Barrett's surveillance are excluded this is more significant. Solution (7.2 min (6.2–8.2)) vs standard control (8.8 min (7.3–10.1), p<0.041) vs placebo control (10.2 min (8.6–11.8), p<0.0031).

Conclusion Premedication with NAC and simethicone is a low cost and well-tolerated method of dramatically improving visibility and procedure time during diagnostic gastroscopy. This simple intervention may improve detection of early gastric cancer.

Competing interests None declared.

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