Determination of the optimal technique for bipolar electrocoagulation treatment. An experimental evaluation of the BICAP and Gold probes.

Abstract

The optimal technique for use of bipolar electrocoagulation has not been established despite its widespread clinical use. This study of the BICAP (Circon-ACMI, Stamford, CT) and Gold (Microvasive, Watertown, MA) probes evaluates the maximal force that can be applied through an endoscope and quantifies the depths of coagulation and sticking at varying parameters in a beef liver model. Maximal forces of application were determined with 3.2- and 2.3-mm probes extended 3 and 6 cm outside the endoscope at 90 degrees and 45 degrees. Depths of coagulation and sticking were measured at 90 combinations of varying forces of application (0, 50, and 100 g), watt settings (1, 3, 5, 7, and 9), and durations (2, 6, 10, and 14 seconds; 3 x 2 seconds, 7 x 2 seconds) for the 3.2-mm BICAP and Gold probes. Mean maximal force of application decreased with greater extension or angulation of the probe outside the scope (3.2-mm BICAP--90 degrees: 3 cm, 110 g; 6 cm, 56 g; 45 degrees: 3 cm, 50 g; 6 cm, 30 g; P less than 0.001; 3.2-mm Gold--90 degrees: 3 cm, 130 g; 6 cm, 105 g; 45 degrees: 3 cm, 62 g; 6 cm, 48 g; P less than 0.001). The maximal force was significantly greater with the Gold probe than with the BICAP in seven of eight comparisons. Significant variations among the mean depths of coagulation (in millimeters) for pooled data of each parameter were observed with force of application (BICAP: 0 g, 0.8; 50 g, 1.4; 100 g, 1.7), watt settings (BICAP: 1, 0.6; 3, 1.7; 5, 1.4; 7, 1.4; 9, 1.3), and duration of treatment (BICAP: 2 seconds, 0.8; 6 seconds, 1.1; 10 seconds, 1.4; 14 seconds, 1.5; values for the Gold probe were comparable). The greatest depths of coagulation were observed at 100 g force, watt setting 3, and 14 seconds or 7 x 2 seconds duration. Sticking paralleled depth of coagulation, increasing with force and duration of application. In conclusion, optimal treatment of bleeding gastroduodenal lesions with bipolar electrocoagulation includes (a) placing the tip of the endoscope en face as close as possible to the bleeding lesion, (b) applying the maximal force possible, (c) using a low-watt setting (approximately 3), and (d) treating with prolonged periods of coagulation.