"Flying lead" bipolar electrosurgical cables can be inappropriately connected to the monopolar electrode jacks on general-purpose electrosurgical units (ESUs). Such misconnections can lead to inadvertent ESU activation and unintentional patient burns or other injury (e.g., bowel perforation).
Flying lead cables are bifurcated at the plug end with two separate connectors. Each connector is intended to be inserted into one of the two bipolar electrode jacks on the ESU. However, the physical separation of these connectors (because they have flying leads) allows them to be inappropriately inserted into the wrong electrode jacks on the ESU (see the figure).
When a bipolar electrode is wrongly connected to the monopolar jacks on an ESU, the generator may, under certain circumstances, activate without intervention from the surgeon. Inadvertent activation is possible if, while the patient is in contact with a monopolar return electrode that is connected to the ESU, the tips of the bipolar electrode touch each other or are applied across conductive tissue.
This unintended activation of the ESU will deliver monopolar output current through the bipolar electrode to the monopolar return electrode in contact with the patient. Further, the monopolar output may be an inappropriate waveform and/or power setting for the intended bipolar procedure.
Left image: Incorrect connection. The separate connectors at the ends of the "flying lead" bipolar electrosurgical cable should never be inserted into two of the ESU's monopolar electrode jacks. The connectors should instead be inserted into the two bipolar electrode jacks (bottom left of the unit). Center and right images: Molded monopolar and bipolar electrode cable plugs are designed to prevent misconnections.
Amid Warnings, Use of Flying Leads Continues
The use of bipolar electrodes with flying lead cables should be a thing of the past. The misconnection risk has existed for decades, and bipolar electrode cables with molded bipolar plugs—a design that prevents misconnections—are now commonly available.
Safety and standards organizations have long made the dangers clear:
1. The flying lead cable design has been warned against in recognized device standards as far back as 1993.
2. ANSI/AAMI/IEC 60601-2-2:2017—and versions dating back to 2006—is a universally recognized voluntary consensus standard pertaining to high-frequency surgical equipment and related accessories. This standard specifically prohibits flying lead cables because of the possibility of misconnection of a bipolar accessory to a monopolar output, which could lead to patient injury. Nevertheless, some manufacturers continue to provide the flying lead cables.
3. Since 2014, ECRI Institute has recommended that facilities phase out flying lead cables (see
Hazard Report H0236).
Nevertheless, flying lead cables remain available, and ECRI Institute continues to receive reports of misconnections resulting in patient injuries. In response, we began recommending in May 2018 (see
Hazard Report H0446) that healthcare facilities entirely discontinue the use of flying lead cables.
Cost is one reason that, despite the risk, healthcare facilities may persist in the use of bipolar electrodes with flying lead bipolar cables. ECRI Institute PriceGuide data confirms that bipolar cables with molded plugs can be 2% to 16% more expensive than electrodes with flying lead cables, depending on the supplier.
However, analyses of purchase costs don't factor in the expense of an adverse incident. The cost of a single burn-related claim may significantly outweigh the added expense of molded plugs. In a retrospective study, payouts for the plaintiffs in surgical burn cases ranged from $82,000 to $518,000, with a median payout of $215,000 (Choudhry et al. 2017). While this data is not specific to burns caused by bipolar-monopolar misconnection, it gives a general idea of the comparative cost of surgical burn litigation.
Some manufacturers have addressed the flying lead cable safety concern. For instance, one currently available ESU includes a feature that prevents activation if flying lead cables are plugged into its monopolar jacks. However, electrosurgical accessory manufacturers and third-party distributors continue to sell flying lead bipolar cables and bipolar electrodes with integral flying lead cables.
How Misconnections—and Inadvertent Activations—Can Happen
Monopolar/bipolar ESUs include differently configured output sockets for each type of electrode:
1. Monopolar output sockets have three unevenly spaced banana jacks in a straight horizontal line to accommodate the three banana pins of the molded monopolar electrode cable plug. (One jack is for the active electrosurgical current and the other jacks are for switching between cut and coagulation modes; the surgeon can switch modes by pressing the appropriate hand-switched button on the active electrode pencil.) The fixed, uneven spacing of the pins prevents this molded plug from being installed upside down or in the bipolar output socket.
2. The bipolar output socket has two banana jacks in a horizontal line that accommodate two bipolar electrode banana pins from a molded bipolar electrode cable plug or from the flying lead cables.
Because banana pins on flying lead cables have no orientation or spacing constraints, they can be easily inserted into any two of the three monopolar jacks. Further, due to the fact that many ESUs have two monopolar sockets, the potential for misconnection remains even if one of the monopolar sockets is occupied by a molded electrode cable plug.
There are three possible ways to misconnect the two banana pins of a flying lead cable into the three available monopolar jacks. In two of these combinations (i.e., when plugged into one of the cut or coagulation mode jacks as well as the active current jack), monopolar current may be delivered through the bipolar instrument when its tips touch or when it closes around tissue with a low enough impedance to conduct the electrosurgical current. In these circumstances, if a return electrode is plugged into the generator and in contact with the patient, as is typical for monopolar operation, the ESU will detect a completed monopolar patient circuit and may inadvertently activate.
ECRI Institute Recommendations
1. The surest way to prevent this problem is to discard disposable and reusable bipolar electrodes with flying lead cables and replace them only with bipolar electrode cables that have a molded plug. These cables cannot be plugged into monopolar output sockets.
2. ECRI Institute recognizes that in very limited circumstances, the above recommendation may not be feasible. That is, some facilities may still own older, specialized bipolar ESUs (e.g., surgeon-preference generators for neurological applications) that do not feature the standard bipolar-jack spacing found on most modern ESUs, and thus require the use of flying lead cables. If your facility uses these units:
a) Segregate them and their flying lead cables from any monopolar or monopolar/bipolar general-purpose ESUs so that their cables cannot be accidentally misconnected.
b) Do not use these specialty bipolar units if there is an alternative energy source that can perform the same function.
c) Plan for the replacement and retirement of units that require flying lead cables.
d) After retiring the units, discard any reusable or disposable flying lead cables that have been purchased for use with them.
3. Regardless of the type of ESU used, always be aware of the specific tones and indicators associated with activation of particular ESU outputs (e.g., cut, coag, bipolar).