Hydrogen leak test is minimally invasive and highly specific for assessment of the integrity of the luminal closure after natural orifice transluminal endoscopic surgery procedures (with video)

Background Leak-resistant closure of transluminal access is a major challenge facing natural orifice transluminal endoscopic surgery (NOTES). Objective To evaluate a hydrogen (H2 )-based leak test for assessment of transluminal-access closure integrity after NOTES procedures. Setting Nine acute porcine experiments. Design and Intervention After gastric-wall puncture and balloon dilation, peritoneoscopy was performed, followed by transmural closure of the gastric opening. The animals were randomly assigned to complete or incomplete closure groups. The H2 leak test was performed by using 1000 mL of 4% H2 gas mixture and the Hydrogen Leak Detector H2000+. The animals were then euthanized for a methylene blue (MB) test of gastric closure integrity. Main Outcome Measurement Intraperitoneal H2 concentration after gastric insufflation with H2. Results The H2 leak test was quick and easy. Intraperitoneal H2 concentrations in parts per million in both groups were similar at baseline (mean ± SD, 0.18 ± 0.29 parts per million [ppm] vs 0.22 ± 0.35 ppm, P = .97) and after balloon dilation (414.8 ± 198.5 ppm vs 601.3 ± 116.1 ppm, P > .99). Postclosure intraperitoneal H2 concentrations dropped to 0.01 ± 0.77 ppm in the complete-closure group, similar ( P = .81) to matched-pairs preopening levels and significantly lower than in the incomplete-closure group (162.0 ± 83.0 ppm, P < .02). On necropsy, the MB test was negative in all 5 animals of the complete-closure group and positive in all 4 animals of the incomplete-closure group. A cutoff of 25 ppm in intraperitoneal H2 concentration after closure gave 100% sensitivity, specificity, and positive and negative predictive values for MB leakage. Limitations Nonsurvival animal experiments. Conclusions The H2 leak test is highly accurate for detection of leakage after NOTES procedures and could become a substitute for currently used MB leak tests.