LAPAROSCOPIC CAPACITANCE - A MYSTERY MEASURED - EXPERIMENTS IN PIGS WITH CONFIRMATION IN THE ENGINEERING LABORATORY

OBJECTIVES: Our purpose was to determine whether capacitive currents i nduced in operative laparoscopes during endoscopic electrosurgery can cause unintentional injury and to measure these currents in the labora tory. STUDY DESIGN: In five anesthetized live pigs we tested whether c apacitive currents generated in operative laparoscopes by unipolar ins truments cause serosal injury. These currents were then measured in th e clinical engineering laboratory. RESULTS: In the setting examined by us serosal injury by capacitive currents occurred only with high gene rator output power. In the laboratory the maximum power of these capac itive currents measured 2.5 W. CONCLUSIONS: Capacitive coupling betwee n unipolar instruments and 10 mm operating laparoscopes requires relat ively high generator output to cause serosal injury. Lower generator o utput settings may cause injury with electrosurgical generators capabl e of higher voltages than the units used in this study