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Managing a New Class of Electrosurgical Risk:
Active Electrode Monitoring
By Vangie Dennis, RN, CNOR, and Beth Grimes, RN, BSN,CNOR
Use of monopolar electrosurgery has always carried the risk of skin injury as a result of return electrode placement. In recent years, this risk has been almost completely eliminated through intense education of perioperative personnel, and the technological developments of "isolated" generators and return electrode monitoring (REM), both of which are now standards of care. However, the serious risk of stray electrosurgical burns (internal thermal burns to non-target tissue) resulting from the laparoscopic application of monopolar electrosurgery still exists. And unlike skin injuries, stray electrosurgical burns can be fatal.
Since the 1930s, the electrosurgery unit (ESU) has been the standard surgical tool, used to cut, coagulate, and vaporize tissue. It is ironic that while surgeons wanting to use a laser for surgical procedures must be credentialed on laser equipment (trained on specific wavelengths, in specific specialties, and proctored by most hospitals before using the laser independently), the ESU, with far more variables to control, requires no such credentialing. Furthermore, there is a lack of awareness about recent technological advancements, such as active electrode monitoring, that can help protect patients from the dangers of stray electrosurgical energy during laparoscopy.
Laparoscopy has made a significant impact in the past decade. There are more than 2.3 million laparoscopic procedures performed annually in the United States and this number is rising at a rate of 2% to 3% per year. By 2010, total laparoscopic procedures in the US are projected to exceed 3 million.1 The increased use of laparoscopic techniques, coupled with the fact that more than 85% of surgeons use monopolar electrosurgery for laparoscopic procedures1, means that more and more patients are being exposed to a new and different class of electrosurgical risk--the risk of stray electrosurgical burns.
During laparoscopic surgery, the surgeon views the peritoneal cavity through micro-cameras introduced into the abdominal cavity through small ports. Thus, the surgeon's field of view is limited to 3 to 5cm (1 to 2 inches). Stray electrosurgical energy occurring outside this field of view can cause unintended burns to non-target tissue, and these burns usually go unnoticed. The Physician Insurers Association of America (PIAA) Laparoscopic Procedure Study found that in "3 out of every 4 cases in which a [laparoscopic] injury [including thermal injury] occurred, it was not recognized prior to the conclusion of the procedure."1 Because they are difficult to detect, stray electrosurgical burns are likely to be misdiagnosed when they present later1, usually in the form of fever and abdominal pain three to seven days after surgery.1 The injuries attributable to stray energy burns are less understood than other surgical injuries partially because of the difficulty of detection and, therefore, diagnosis. Injured areas may become compromised by a secondary infection making the identification of the primary cause difficult. Thus complications resulting from stray electrosurgical burns may be erroneously attributed to another cause, such as instrument laceration.
Laparoscopy is still primarily rigid scope delivery and the eyes of the scope are on the distal tip; scopes cannot "look back on themselves." Because of this constraint, some surgeons use "last-look technique," in which they release the gas from the abdomen slowly while visually checking for injury or bleeding before removing the trocar. Unfortunately, last-look technique is not a routine practice, though it should be. More commonly, the trocar sheath is removed after the gas is manually depressed from the abdomen. If an injury has occurred, the likelihood of it being noticed is very slight.
The stray electrosurgical energy that causes burns is a result of insulation failure, capacitive coupling, and direct coupling. Direct coupling or "pilot error" is within the surgeon's control and will not be discussed here. Insulation failure and capacitive coupling, however, are beyond the surgeon's control. When using conventional, non-shielded instruments, primary insulation is the first and only line of defense against stray electrosurgical burns. The life expectancy of a reusable instrument is calculated at about one year. With emphasis on cost containment in surgery, facilities are using instrumentation beyond their expected life. Most hospitals have no formal protocol for testing to ensure that the surgeon is handed an instrument free from insulation failure. Inspection of instruments before and after use may help reduce the risk, but because this technique is user-dependent, it is not fail-safe. Minute insulation defects cannot be detected by even the most vigilant of staff and inspection does not prevent insulation failure from occurring during a procedure. More than 500 surgeons surveyed at a meeting of the American College of Surgeons (ACS) were asked if they had ever "seen or heard of insulation degradation on monopolar electrosurgical probes." Seventy-one percent of respondents answered "yes."1
Insulation failure can occur as a result of the constant introduction and removal of the instrument during surgery, high voltages, general handling, and the stresses of sterile processing. A small insulation defect is actually more dangerous than a large one; the smaller the defect, the higher the current density transferred to nearby non-target tissue, the greater the chance of an electrosurgical burn. A high-voltage waveform (such as those used during coagulation) will create a larger hole in the insulation or create a hole in weak insulation. The ACS survey asked surgeons "what setting they used most of the time during laparoscopy," 74% answered "coagulation."1 During monopolar electrosurgery, the temperature of the electrosurgical current can be up to 700°C. The resting temperature of tissue is 32°C. Tissue death will occur at 44°C. If an insulation defect occurs during a procedure, the surgeon will not notice a change in the current delivered at the tip.
Capacitive coupling can also cause stray electrosurgical burns. As the number of laparoscopies performed has increased, the need to lessen the responsibility of processing instruments has resulted in facilities using disposable instruments and trocars as well as reusable instruments. The mixing of reusable and disposable instruments, which also mixes conductive and non-conductive materials, facilitates capacitive coupling. Capacitive coupling occurs in the presence of a capacitator, created when two conductors are separated by an insulator. This situation can occur many times throughout a laparoscopic procedure, as tissue, trocar, and instrument (itself consisting of active electrode and primary insulation) are in close proximity. Capacitive coupling can transfer current to non-target tissue through intact insulation, thereby causing stray electrosurgical burns. In the ACS survey, 49% of surgeons said they had not heard of "capacitive coupling."1
Stray electrosurgical energy because of insulation failure and capacitive coupling can cause bowel perforation, or a burn that may later lead to bowel perforation, resulting in leakage of the intestinal contents into the peritoneal cavity (i.e., fecal peritonitis). Although rare in occurrence, a generally accepted incidence of unexpected burns to the bowel during laparoscopic electrosurgery is 1% to 2%.1 Bowel injury and resulting complications account for most of the fatalities associated with laparoscopic procedures; even with modern "antibiotics, the mortality rate from fecal peritonitis is approximately 25%."1 Additional complications resulting from stray electrosurgical burns include organ damage and vessel hemorrhage. Clinically significant symptoms of internal burns usually do not present until three to seven days after surgery, placing the patient at risk for delayed diagnosis and treatment.1 Usually patients are at home when they experience symptoms. If they do contact their surgeon or return to the hospital, the symptoms they present with, such as non-specific abdominal pain and a slight rise in temperature, mimic normal post-op symptoms of laparoscopy.
Infections are caused by the interaction of three elements: organisms, tissues, and host defense. Surgery reduces the resistance of the host. Coupled with this, the burned, necrotic, devitalized avascular tissue enhances infection by providing excellent media for microbial growth. The post-op systemic infection of bacteremia/septicemia is from the dissemination of microorganisms into the bloodstream from a distributing focus, the thermal burn. The intestinal tract harbors many microorganisms. Leakage into the peritoneal cavity can be a source of generalized peritoneal sepsis. Anaerobic organisms thrive in an unoxygenated environment. The most common organisms from spillage of contaminants from the enteric flora are Escherida coli and Bacteroides fragilos. Another contributing factor to high mortality, if left untreated, is Clostridium perfringes (a highly resistant gas-producing spore causing gas gangrene). Gram-negative bacilli often are resistant to long-established antibiotics (normally prescribed post-operatively). Because these infections carry a high risk of bacteremia, they require prompt interventions.
AORN has stated in their Recommended Practices for Endoscopic Minimally Invasive Surgery that "perioperative team members should monitor continually the functioning of equipment and the integrity of endoscopic instruments to ensure that hazards are minimized." In the rationale for this statement they point out that "use of active electrode monitoring devices minimizes chance insulation failure, direct coupling, and capacitive coupling."1
Active electrode monitoring eliminates the risk of stray electrosurgical burns resulting from insulation failure and capacitive coupling (Encision Inc., Boulder, Colo, AEM® Laparoscopic Instruments). Under normal operating conditions, AEM technology delivers 100% of the power to the surgeon's intended site. Capacitively coupled energy is drained to the generator via a protective shield built into 5mm AEM instruments. If primary insulation fails or the level of capacitively coupled current becomes too much, AEM technology shuts down the generator, thereby protecting the patient from a life-threatening burn, and alerts the perioperative staff. Unintended laparoscopic burns now are preventable with the introduction of AEM.
The danger stray electrosurgical burns represent to the patient mandates use of AEM technology for all laparoscopic procedures. To ensure patient safety, AEM technology must become a standard of care. AEM technology provides us with an efficacious, reusable, and cost-effective system that requires no change in surgical technique for the surgeon, and essentially eliminates the chance of catastrophic patient injury from thermal damage to tissue.
The perioperative management professional has the opportunity to protect the patient from the dangers of stray electrosurgical burns incurred during laparoscopic surgery. When primary insulation fails or capacitive coupling occurs, AEM protects the patient from a life-threatening burn. Unintended laparoscopic burns now are preventable with the advancement of active electrode monitoring.
Vangie Dennis, RN, CNOR, and Beth Grimes, RN, BSN, CNOR.
For a list of references, see the Infection Control Today® Web site.For a complete list of references click here