RESUMO
STUDY OBJECTIVE: To compare rates of production of gases generated by VersaPoint bipolar hysteroscopic vaporizing electrodes using normal saline and monopolar vaporizing electrodes using 1.5% glycine. DESIGN: In vitro study (Canadian Task Force classification II-1). SETTING: Laboratory. MATERIAL: Bovine cardiac muscle. INTERVENTION: Fresh morbid bovine cardiac muscle was fully immersed in normal saline for the bipolar system and in 1.5% glycine for monopolar systems. Loop and bulk vaporizing electrodes were activated by radiofrequency electrosurgical units (ESUs) appropriate for each system, at standard powers and at settings higher than those in clinical use. MEASUREMENTS AND MAIN RESULTS: Rates of gas production were calculated and data analyzed by analysis of variance. For bulk vaporizing electrodes, the highest gas production rates at standard settings occurred with monopolar electrodes and the Force 2 generator at 300 W, and the Force FX at 200 W. At slightly higher than standard 200-W settings, the VersaPoint bipolar bulk vaporizing electrode was associated with lowest gas production rates in this category. Although there were statistically significant differences between loop electrodes, the magnitude remained small at similar ESU settings, and differences are thought to be clinically insignificant. CONCLUSION: Rates of gas production in this model appeared to vary most with ESU power output settings and relatively little with electrosurgical modality (bipolar or monopolar).
