Electrosurgery-induced generation of gases: comparison of in vitro rates of production using bipolar and monopolar electrodes.

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).