Comparison of endoscopic electrocoagulation and laser photocoagulation of bleeding canine gastric ulcers

The most promising endoscopic hemostatic techniques all depend upon heat to coagulate. Four thermally active techniques under similar controlled conditions in this endoscopic study were compared. The study was undertaken to compare the efficacy and histologic damage of monopolar electrocoagulation (MPEC), bipolar electrocoagulation (BPEC), argon laser photocoagulation (ALP) and neodymium-yytrium-aluminum-garnet (YAG) laser photocoagulation applied endoscopically to control bleeding from standard canine gastric ulcers. An open-closed model utilizing a nontraumatic intestinal clamp in heparinized adult mongrel dogs was used. Bleeding ulcers were randomly assigned to an endoscopic treatment modality or control. The endoscopic techniques and parameters of treatment for this study were established from a previous experience with each modality and from endoscopic treatment in pilot studies. Quantitative efficacy and subjective ease of endoscopic treatment were evaluated acutely; gross and histologic injury were determined after 7 days. Our conclusions were that more energy or greater power was required with each method to treat bleeding standard ulcers efficiently through the endoscope than at laparotomy. It was also concluded that each method was 93% or more effective in halting bleeding in this canine ulcer model but there were differences in ease of endoscopic use. Both lasers were much easier to apply than electrocoagulation. The order of decreasing ease of application was YAG, ALP, MPEC, BPEC. Argon laser and BPEC caused significantly less tissue injury than either MPEC or YAG. The order of increasing injury or decreasing margin of safety was ALP, BPEC, YAG and MPEC. In contrast to electrocoagulation, especially monopolar, laser related tissue injury was generally predictable and correlated with total treatment energy, animal weight or gastric overdistension, or both. The limitations, advantages, and disadvantages of each hemostatic technique are discussed and compared.