How to Properly Position a Neutral Electrode?

Proper Application, Conductivity, and Patient Safety Guidelines for High-Frequency Electrosurgical Neutral Electrodes

During high-frequency electrosurgery, all high-frequency current entering the patient through the active monopolar electrode must be returned through the neutral electrode and then transferred back to the electrosurgical unit through the neutral electrode cable and connector. Therefore, the condition of the Return Electrode, the reliability of its connection, and its proper placement on the patient's skin are all important for safe electrosurgical procedures.

If the neutral electrode is not properly connected to the patient or is incorrectly connected, current may leave the patient's body through unintended contact with conductive objects such as the operating table, supports, other equipment components, or wet materials. Because these contact areas are usually relatively small, the local current density may become excessively high, potentially causing tissue damage and, in severe cases, patient burns.

Why Do Burns Occur During High-Frequency Surgery?

Patient burns during high-frequency surgery can have different causes. Understanding the mechanisms behind these injuries can help healthcare professionals take appropriate preventive measures when using an electrosurgical neutral electrode.

Depending on their cause, burns during high-frequency surgery can generally be classified into three categories:

• Endogenous burns
• Exogenous burns
• Pseudo-burns

Among these, endogenous burns are associated with excessively high current density within the patient's tissue.

How Are Endogenous Burns Related to Neutral Electrodes?

During monopolar electrosurgery, a relatively high current density is required at the active electrode to cut or coagulate tissue. However, at the neutral electrode, the current needs to return to the electrosurgical unit through a much larger effective contact area. Therefore, the current density at the neutral electrode should remain sufficiently low.

If the available conductive area of the neutral electrode is too small to handle the radiofrequency power being used, current may become concentrated in a limited area. Therefore, when selecting a high-frequency surgical neutral electrode, it is important to consider the available conductive area in relation to the actual RF power used during the procedure.

Is the Available Conductive Area of the Neutral Electrode Sufficient?

The minimum conductive area required for a neutral electrode depends on the maximum radiofrequency power used during the electrosurgical procedure. Different types of neutral electrodes may have different conductive structures, including conductive silicone electrodes, metal plate or metal foil electrodes, and electrodes with a uniformly applied conductive gel.

In practical applications, users should ensure that the available conductive area of the Grounding Pad is sufficient for the RF power used during the procedure. For special patient groups, such as infants and young children, the appropriate electrode size may be determined according to the actual maximum RF power used during the procedure rather than simply referring to the maximum rated power of the electrosurgical unit.

Important consideration: Is the available conductive area of the neutral electrode large enough to safely accommodate the RF power being used?

Why Can the Effective Conductive Area of a Neutral Electrode Decrease?

The effective conductive area of a neutral electrode refers to the area that maintains good electrical contact with the patient's skin and effectively conducts current. Even when the physical size of the electrode is sufficient, the effective area may become smaller if proper skin contact is not maintained, potentially resulting in increased local current density.

When using a Negative Plate, particular attention should be paid to the following factors:

1. Improper Neutral Electrode Placement

The neutral electrode must be completely and securely applied to the patient's skin and, where appropriate, positioned as close as practical to the surgical site. Care should also be taken to ensure that the electrode does not become detached or slide when the patient moves or changes position. Depending on the procedure, suitable locations such as the upper arm or thigh may be considered.

Important consideration: Has the neutral electrode been completely and correctly applied to the patient's skin?

2. Damaged Conductivity of the Neutral Electrode

Oxidation, dried blood, oils, and other contaminants on the electrode surface may reduce the conductivity of the neutral electrode. If the electrode surface is contaminated or visibly damaged, its effective conductive area may also be reduced.

Important consideration: Is the neutral electrode clean, intact, and free from significant oxidation or damage?

3. Improper Application of Conductive Gel

For electrodes that require conductive gel, the gel should be applied evenly across the effective conductive area. If the gel covers only part of the electrode, or becomes dried or unevenly distributed, local conductivity may become inconsistent.

Important consideration: Is the conductive gel fresh and evenly distributed across the conductive area of the neutral electrode?

4. Neutral Electrode Failure

Oxidation, mechanical overload, or other factors may damage the electrode surface or cause separation between the electrode and its connection components. In such cases, current may become concentrated over a smaller effective area, resulting in increased local current density.

Important consideration: Are there any signs of damage or abnormality in the electrode or its connection components?

5. Incorrect Neutral Electrode Orientation

The neutral electrode pad must be positioned according to the product design and instructions for use. If the insulating side is placed against the patient's skin instead of the intended conductive side, the required electrical pathway cannot be properly established.

Important consideration: Is the conductive side of the neutral electrode correctly facing the patient's skin?

6. Conductive Liquids on the Neutral Electrode

Blood, saline solution, or other conductive liquids between the neutral electrode and the patient's skin may cause current to concentrate in localized wet areas. Therefore, during high-frequency surgery, the electrode contact area should be kept in accordance with the product's intended use requirements.

Important consideration: Are there any conductive liquids, such as blood or saline solution, on or around the neutral electrode?

Choosing the Right Neutral Electrode for Safer Electrosurgery

Proper selection and use of a Patient Return Electrode involves more than choosing the appropriate electrode size and conductive area. The electrode's integrity, cable and connector condition, and actual contact with the patient's skin should also be checked before use. For disposable products, users should confirm that the electrode is in good condition and apply and connect it according to the applicable instructions for use.

CMAI is a professional medical electrode manufacturer providing neutral electrodes, disposable neutral electrodes, and customized electrosurgical electrodes. We support OEM/ODM customization of different sizes, materials, connection methods, and electrode structures, providing customized electrode solutions for high-frequency electrosurgical equipment and related medical devices.