Capacitive coupling Photo courtesy of Encision

Without realizing it, many surgeons expose their patients to a potential danger that’s all too common during minimally invasive surgery but easily preventable and expose their malpractice security to needless risk.

It involves electrosurgical units, which surgeons have used to cut and coagulate tissue in open procedures for more than 70 years, and in minimally invasive surgical (MIS) procedures since their inception in the early 1980s. These days surgeons use ESUs in about 80 percent of all surgical procedures.

While the emergence and widespread use of isolated electrosurgical generators and contact quality monitoring or return electrode monitoring (REM) reduced the risk for alternate ground site burns and burns at the return electrode site on patients during open procedures, those technological advancements don’t address a growing problem that occurs during laparoscopic procedures – stray energy burns.

Certainly these stray energy burns, which damage internal organs and tissue, can happen during open procedures, too, according to clinical experts, but the main difference is that surgeons are less likely to spot them during MIS procedures. A lacerated or punctured common bile duct or a bowel perforation, two common injuries during MIS procedures as noted in a Physician Insurers Association of America study a decade ago, are noticeable. And they can easily be classified as a medical error committed by the surgeon.

But a minute tissue burn, undetected and consequently untreated by the surgeon, can result in a patient returning to the emergency room several days post-surgery feeling sick with severe abdominal pain and suffering from an infection. Post-operative complications can include peritonitis and sepsis, two conditions that can lead to death. What’s important to note is that the infection most likely won’t be traced to a stray energy burn. As a result, it’s difficult, if not nearly impossible to classify that as a proven medical error committed by the surgeon. At least not yet.

So how can a surgeon not see a stray energy burn? It’s easy. During a minimally invasive surgical procedure a surgeon can see directly the handle of the instrument he or she is holding and manipulating and on a viewscreen the distal tip of the instrument inside the patient cavity. What the surgeon can’t see is the rest of the instrument between those two points – the trocar cannula and the active electrode shaft, from which stray energy can "leak" out.

Stray energy roots
If clinicians typically can’t connect the dots between a patient’s post-surgical complications and stray energy burns they generally know what causes the stray energy burns. Three factors lead to stray energy burns. They are direct coupling, capacitive coupling and insulation failure.

Megadyne E-Z Pen

Direct coupling happens when the active electrode either touches or comes too close to another metal instrument within the body cavity. For example, a surgeon may accidentally bump the active electrode into the telescope through which he or she views the surgery or simply move it too close to the other so that both instruments conduct a current and potentially burn internal tissue or even skin. Generally, surgeons have the most control over this cause because they can see warning signs of direct coupling, which are electrical sparks or arcing currents.

Capacitive coupling occurs when an electrical current moves from one conductor, such as a metal instrument or active electrode, to another conductor, such as a metal instrument or organic tissue, through a non-conductor or insulator, causing serious patient burns.

Clinical product specialists at Valleylab (Boulder, CO) offered a simple explanation of how this works via their "Clinical Information Hotline News" service. "A capacitor is created by inserting an insulated active electrode down a metal cannula. Capacitively coupled electrical current can be transferred from the active electrode, through intact insulation, and into the conductive metal cannula. If the cannula then comes into contact with body structures, that energy can be discharged into these structures and cause injury. With an all-metal cannula, electrical energy stored in the cannula will tend to disperse into the patient through the relatively large contact area between the cannula and the abdominal wall."

Valleylab’s experts call capacitive coupling "the most complicated of stray current injuries and also the least understood."

Unfortunately, experts agree that there’s no way to eliminate capacitively coupled current because it always happens when an electrosurgical current is generated. Where surgeons can make the difference is by lowering power settings and controlling electrode activation. That includes only activating the electrode intermittently when the tip touches tissue and when the electrode isn’t near or in contact with other instruments, according to Valleylab.

While direct and capacitive coupling can be controlled by surgeon manipulation, insulation failure represents the wild card.

Insulation failure occurs when the insulation material that shields the active electrode shaft breaks down or degrades, providing an escape route for electrical energy to "leak" from the electrode and burn tissue. An insulation failure may be as tiny as a microscopic hole but still generate dangerous consequences. In fact, "the smaller the defect, the greater the hazard," according to experts at Encision Inc. (Boulder, CO). How is that possible? Simply put, any holes that may be invisible to the naked eye can concentrate the density of the current so that a more powerful current escapes and burns nearby tissue.

How do insulation failures in reusable and disposable active electrodes develop? Valleylab and Encision traced it to at least six possible causes.

1. Poor manufacturing practices.

2. Microscopic imperfections.

3. Wear-and-tear during normal use, including cleaning and high-temperature sterilization and the long-term stress of high-voltage electrical currents passing through the electrodes.

4. Damage from improper handling, including accidental nicks from sharp objects.

5. Improper sterilization (or not following the manufacturer’s guidelines).

6. Re-sterilizing the instrument if it’s labeled single-use only.

ECRI hosted an audio conference, "Electrosurgery and Patient Safety: Critical Measures for Minimizing Risk," in mid-March. The independent nonprofit health services research agency queried the estimated 1,500 attendees on whether any of their facilities experienced electrosurgical burns during the past year. Of the estimated total, more than 47 percent responded one or two; another nearly 3 percent answered "several."

Although the impromptu survey didn’t specify whether any of these burns were due to stray energy clearly awareness of the issue is growing.

Several physician and nursing professional organizations have issued guidelines and recommendations on how to prevent stray energy burns. For example, the Association of periOperative Registered Nurses (AORN) issued in its 1998 recommended practices for electrosurgery that "the active electrode should be inspected for damage and impaired insulation at the operative field before use." In January 2004, AORN noted in an update of its recommended practices for electrosurgery that the "use of active electrode shielding and monitoring minimizes the risks of insulation failure and capacitive-coupling injuries."

Fighting back
Short of implementing specific policies and procedures to protect patients, as well as clinicians, from the dangers of stray energy burns, hospitals and other healthcare facilities can choose from a number of product options that offer varying degrees of relief.

One of the more recent and more comprehensive options is active electrode monitoring (AEM), which debuted about five years ago. Launched by Encision (formerly known as Electroscope Inc.) and its co-founder Roger Odell (who previously spent 15 years as an engineering expert at Valleylab), AEM works similarly to ground fault interrupter (GFI) electric outlets, which replace standard electric outlets in your house.

Essentially, Encision’s AEM laparoscopic instruments continuously monitor the active electrode instrument through a coaxial conductive protective shield that is sandwiched between a primary insulation layer around the active electrode and an outer insulation layer covering the shield. When the AEM instrument detects the release of stray energy the AEM monitor interrupts the power transmission by shutting down the electrosurgical generator.

Just as GFI outlets function as standard outlets but with an additional safety feature, the AEM instruments and monitors function like standard electrosurgical units but are equipped with this emergency shutdown feature.

Whether a surgeon works with reusable or disposable electrodes to plug into the electrosurgical unit the healthcare facility eventually has to replace the instruments. If healthcare facilities choose not to replace those instruments with the AEM models for whatever reason (Encision noted that its instruments are "cost-neutral" and don’t require the surgeon to alter his or her technique in any way, removing the economic and operational hurdles) they have other choices.

Back in the late 1990s, a company called MediCor Corp. developed a testing product called InsulScan that enabled clinicians to check the condition of the electrode’s insulation. Mick Reed, president of Mobile Instrument Service & Repair Inc. (Bellefontaine, OH), a long-time service company, liked the product so much that he agreed to market it through his company. Medline Industries Inc. (Mundelein, IL) also sells InsulScan.

Basically, InsulScan serves as an electrosurgical instrument insulation tester for the operating room that can be used before and immediately after a surgical procedure. Mobile Instrument recommends that clinicians use the testing wands to scan electrosurgical instruments prior to a case beginning so that any insulation defects can be exposed and those reusable instruments removed and reinsulated. "One last scan post-operatively will confirm for the patient’s surgical chart that no defects occurred during surgery," the company added.

Even though AEM instruments seemingly obviate the need for testing products to check reusable devices that routinely are run through the sterilization process and testing products enable facilities to retain their existing instruments until replacements are warranted, another alternative involves simply purchasing disposable instruments (which are not immune to damage from handling or manufacturing and material defects) or so-called "resposable" instruments.

One noteworthy line of "resposable" electrosurgical instruments is offered by Megadyne Medical Products Inc. (Draper, UT). Its new E-Z Clean Resposable Laparoscopic Electrodes feature disposable E-Z Clean MegaTIPs for the distal end of the instruments and reusable Indicator Shafts to house the active electrode. The Indicator Shafts sport two layers of insulation that can safely be cleaned and sterilized by standard and flash steam cycles, as well as ethylene oxide cycles. When the outer insulation layer is worn, nicked or cut, the yellow base or inner insulation shows through, telling the clinician to replace the electrode.

Questions to ponder
Clearly, the existence of and potential for stray energy burns from electrosurgical units represents an ongoing problem for open and MIS procedures. Stray energy burns not only harm the patient (sometimes fatally) but also increase the risks for financial liability of the surgeon and the healthcare facility in which he or she practices medicine.

In an oxygen-rich atmosphere like the O.R., and in particular the draped surgical site, stray energy currents and panicked reactions to sparking or arcing can contribute to much larger surgical fires. In fact, Scott Aronson, principal, Russell Phillips & Associates LLC (Rochester, NY), noted that of the "best sources" for surgical fires electrosurgical units account for 68 percent of them. Aronson’s firm specializes in fire and emergency management for healthcare facilities. Granted, stray energy may account for only a fraction of that total; other causes include equipment malfunctions beyond the electrodes, poor handling techniques and simple behavioral distractions.

While defective shielding from the manufacturer certainly can happen, according to Genard McCauley, electrosurgery manager at Aaron Medical Corp. (St. Petersburg, FL), "most of the time it’s due to human handling." McCauley acknowledged that trying to prove product defects right out of the package can be difficult unless the person who opens the electrode package scans the instrument and documents the defect at that time, which is atypical.

"A hospital that at least tests its reusable instruments is doing a good job looking out for the safety of its patients and staff," said McCauley. "And the closer you are to the last person handling the device [who] should do the inspection the better.

"But that can’t always happen," he continued. "The O.R.s are very busy places. They may not have time. In order for them to make sure they take the time somebody will have to step in [to encourage behavioral changes.]"

Potential options include professional organizations strengthening their "recommendations" and "considerations" of safer product usage to downright mandates, he acknowledged, but they may not be able to influence behavior in that way. Safer product usage could be tied to accreditation by agencies such as the Joint Commission on Accreditation of Healthcare Organizations, or to quality-based reimbursement and administrative compensation levels.

If stray energy burns from MIS procedures could be conclusively linked to subsequent patient infections and re-admissions, "insurance companies would be all over it," he added.

"People are creatures of habit, especially in the medical field," McCauley noted. "It’s going to cost money and take time. [Professional organizations] can only do so much. The bottom line is that education is key because this issue can cost hospitals millions of dollars." HPN