Complications of electrosurgery can be categorized as: the potential for the explosion of combustible gases, either anesthetics or bowel gas, interference with pacemakers and monitors, neuromuscular stimulation including ventricular fibrillation, accidental burns, and the potential for the transmission of infection.
One of the advantages attributed to electrosurgery was the purported ability to sterilize the field in which it was used. Recent concern sparked by the acquired immunodeficiency syndrome epidemic has prompted reevaluation of this concept. Transfer of both bacteria and viruses by electrosurgical electrodes has been demonstrated, proving that the electrode is not sterilized by the electrical discharge. Because gynecologists are, we hope, unlikely to use electrodes on more than one patient without intervening sterilization, the transmission of disease between patients is unlikely. With the advent of in office electrosurgical excision procedures involving tissues presumably infected by oncogenic subtypes of the human papillomavirus, the gynecologist performing these procedures must be vigilant regarding sterilization technique if disposable electrodes are not used. Steam or gas sterilization is preferred over soaking. Of greater concern to the gynecologist is the potential for transmission of disease from patient to physician or ancillary personnel. Colver and Peutherer30 demonstrated that discharge of an electrosurgical current over a droplet of fluid caused spattering over a distance of at least 5 cm. Because electrosurgery causes an expansion of tissue fluids resulting in the explosion of cells, an aerosol of blood and fluid droplets is created that can potentially transmit infectious agents. It is important, regardless of the surgical procedure being performed, that all personnel observe universal precautions. Smoke generated by electrosurgical procedures is mutagenic, giving additional impetus to the recommendation that surgical masks be worn.
Burns to the patient's skin can occur in a variety of ways. The most common mechanism is the alternate site burn, which results from a high current density either at a poorly applied ground electrode, at the site of monitoring devices such as ECG electrodes or temperature probes, or at the sight of accidental contact with a grounded metal object. These burns must be distinguished from decubitus ulcers and chemical burns. All electrosurgical burns are visible at the time of occurrence. Late appearing burns are due to some other factor. Most modern electrosurgical generators are isolated from earth ground, and have fault monitors that will disable the machine and sound an alarm if the ground electrode circuit is not intact. While these features minimize the incidence of alternate pathway burns, several measures can be taken to make them even less likely to occur. Ground electrodes should not be placed under warming blankets, as there will be an additive heating of tissue. The best site for placement of the dispersive electrode is one with low tissue impedance between it and the active electrode. In pelvic surgery, the top of the thigh is the preferred location to minimize the distance between the electrodes. Monitoring devices should not be placed between the active and ground electrodes. There is a marked increase in current through ECG leads when they are positioned in this manner. Most importantly, if an ESU requires unusually high settings to function, a faulty ground should be suspected, and the ground electrode and its entire circuit checked.
Other mechanisms of skin burns involve the ignition of paper drapes or antiseptic solutions, particularly alcohol, used in skin preparation. If alcohol is used to prepare the skin prior to surgery, time should be allowed to ensure that it has fully evaporated prior to draping the patient.
Historically, explosive anesthetic gases posed the greatest explosion risk in the operating room. Fortunately, these agents are rarely used today. If they are used, the surgeon should be so informed, and use of the ESU avoided. Of greater concern is bowel gas, which frequently contains a mixture of methane and hydrogen which, when mixed with oxygen, even in low concentrations, are highly explosive. This is a real hazard when operating around the large bowel, or when performing anorectal surgery.
Nitrous oxide supports combustion, as well as pure oxygen. Many gynecologists use nitrous oxide as a laparoscopic distention medium to avoid the peritoneal irritation caused by carbon dioxide. If electrosurgery is to be used during a laparoscopic operation, the use of nitrous oxide to distend the abdomen should be avoided.
Although most modern cardiac pacemakers are resistant to interference by extraneous electromagnetic signals, several incidences of asystole and cardiac arrest have been reported when electrosurgery is used in patients with pacemakers.These problems occur predominantly in patients with older demand pacers. In these units, the electrosurgical signal may block the pacer's inhibition amplifier allowing an R-on-T phenomenon to occur, leading to ventricular fibrillation. Aside from the special case of the cardiac pacemaker patient, with the use of radio frequency currents, cardiac arrhythmia due to discharge from an ESU should be an almost nonexistent event.
Until the recent upsurge in interest in operative laparoscopy, reports of burns of the bowel during laparoscopic sterilization had rendered the use of unipolar techniques in laparoscopy almost untenable. In 1973, the Complications Committee of the Association of Gynecologic Laparoscopists reported burns to skin or bowel occurring at a rate of 2.3 per 1000 patients undergoing sterilization by unipolar electrosurgery. In the same year, Thompson and Wheeless reported 10 burn injuries of the intestines occurring in a cohort of 3600 patients undergoing unipolar laparoscopic sterilization. Four of these injuries were noted at the time of surgery and treated with observation alone due to the small, superficial nature of the injury. This group experienced uneventful recovery. A fifth patient with a small burn had the site oversewn, although she could have been treated by observation. In five additional cases, the injury was unrecognized and resulted in delayed perforation. Most of the burns occurred on the terminal ileum. As we shall see presently, it is important that burns occurred with both one- and two-puncture techniques. In 1975, Loffer and Pent reviewed the 71 electrical complications of laparoscopy that had been reported at that time. Twenty-five cases involved burn injuries to the abdominal wall, and 44 cases, burns of the bowel. Of these 44 cases, the ileum was involved in 39 and the colon in five. Schwimmer reported two superficial intestinal burns occurring in 410 sterilization procedures performed with a two-puncture technique, using unipolar current. In 1979, Maudsley and Qizilbash reported an additional four small bowel injuries among 7466 consecutive procedures, all performed with a two-puncture technique. The mechanism of these injuries is controversial. Mechanisms involving current arcing to the bowel at distant sites, arcing from tube to bowel, and creation of a capacitor have been proposed. Each of these mechanisms appears equally improbable. It requires about 30,000 volts to cause dielectric breakdown of a 2.5 cm air space.Because the bowel, the active electrode and the dispersive electrode are connected by much lower resistance circuits than air, it is difficult to rationalize sparking between biologic structures although surgeons have reported seeing sparks jumping from the tube to the bowel.
Theoretically and in practice, a capacitor can be inadvertently constructed using unipolar current and a single puncture technique. This would allow several thousands of volts of electrical energy to accumulate in the laparoscope barrel—more than enough to allow arc formation between laparoscope and nearby bowel. Although this mechanism may account for some of the reported injuries, it is unlikely to account for the majority because most cases occurred with a double puncture technique. It is possible that faulty insulation on the unipolar electrode, passed either through an insulated or a metal sheath may account for some of the injuries. Perhaps the most likely mechanism was proposed by Engle and Harris who studied the electrodynamics of tubal coagulation. It was found that, initially, with the electrode in good contact with the intact tube, as tissue heating began, the resistance dropped, and no sparking occurred. As coagulation proceeded and the tissue fluids boiled away, the resistance increased. When resistance became so high that tissue contact was poor, sparking occurred from the electrode to the nearest moist tissue. This effect was related to the peak voltage. It is recommended that tubal coagulation be carried out with the lowest effective power and a cutting current to limit peak voltage. The bipolar electrosurgical forceps have been adapted to gynecologic use as a highly successful remedy to the problem of inadvertent bowel burns.
One additional potential cause of inadvertent electrical injury deserves discussion. When unipolar current is applied to a structure on a stalk, the current tends to concentrate at the base of the stalk causing coagulation of the blood supply to the structure. While this may be applied to advantage in treatment of condylomas and papillomas, there is a potential for disastrous consequences if unipolar coagulation is used to control bleeding during circumcision.