Optimizing Monopolar Coagulation Therapy for Non-Variceal Upper Gastrointestinal Bleeding

Abstract

Purpose: Despite current endoscopic therapeutic modalities, the mortality for non-variceal upper gastrointestinal (GI) bleeding remains at 5 to 10%. Monopolar electrocautery is a proven technology for hemorrhage control in the operating room; however its use in non-variceal upper GI bleeding has been limited by unavailability of appropriate endoscopic devices and the lack of experience with this treatment modality. This study was designed to determine the optimal performance characteristics of an endoscopic monopolar electrocautery device for the upper GI tract. Methods: Female domestic pigs underwent upper endoscopy with inspection of the esophagus and stomach, followed by creation of cautery lesions using a monopolar electrocautery device designed for endoscopic hemostasis control (Coagrasper, Olympus Inc.). Various power settings and durations of coagulation were applied to the greater curve of the stomach. A total of 12 cautery lesions were created in a systematic grid with 2 cm between each lesion. The cautery energy level was tested at 25, 50 and 75 Watts (W), and durations for each of energy level of 2, 3, 4 and 5 seconds using the ESG-100 electrosurgery generator (Olympus Inc.). The extent of cautery was assessed histologically by a pathologist blinded to power settings and treatment durations. The safety of prolonged durations of monopolar coagulation was also evaluated. Results: Four pigs with mean body weight of 58 ± 15 kg were used. The mean diameter of the cautery lesion measured 4.3 ± 1.7 mm for 25W at 2 seconds, with injury reaching only the mucosa; for 25W at 3, 4 and 5 seconds, the lesions measured 4.8 ± 0.5 mm, 5.0 ± 0.0 mm and 6.0 ± 0.8 mm respectively, and the depth of injury reached muscularis mucosa. For lesions created using 50W, the cautery diameter measured 6.8 ± 1.3 mm at 2 seconds, 8.0 ± 2.0 mm at 3 seconds, 8.8 ± 2.1 mm at 4 seconds and 9.0 ± 2.9 mm at 5 seconds. At 50W, the depth of injury reached the submucosa in 50%. For lesions created using 75W, the cautery diameter measured 8.0 ± 0.8 mm at 2 seconds, 9.0 ± 1.8 mm at 3 seconds, 9.3 ± 1.3 mm at 4 seconds and 11.5 ± 2.4 mm at 5 seconds. At 75W, the depth of injury also reached the submucosa in 50%. To determine clinical safety, the duration of coagulation was prolonged to 30 seconds for 25W, 15 seconds for 50W, and 14 seconds for 75W; no acute perforations resulted. Conclusions: The optimal settings for monopolar coagulation during upper endoscopy appear to be 25 watts with durations of therapy between 3 to 5 seconds. Monopolar coagulation is an alternative modality for endoscopic management of non-variceal upper gastrointestinal bleeding.