Laparoscopic capacitance: a mystery measured. Experiments in pigs with confirmation in the engineering laboratory.

Abstract

Our purpose was to determine whether capacitive currents induced in operative laparoscopes during endoscopic electrosurgery can cause unintentional injury and to measure these currents in the laboratory. In five anesthetized live pigs we tested whether capacitive currents generated in operative laparoscopes by unipolar instruments cause serosal injury. These currents were then measured in the clinical engineering laboratory. In the setting examined by us serosal injury by capacitive currents occurred only with high generator output power. In the laboratory the maximum power of these capacitive currents measured 2.5 W. Capacitive coupling between unipolar instruments and 10 mm operating laparoscopes requires relatively high generator output to cause serosal injury. Lower generator output settings may cause injury with electrosurgical generators capable of higher voltages than the units used in this study (Valleylab SSE2L and Force 2).