The instruction to remove nail polish, including gels and acrylics, before any surgical procedure is a standard preparation step in healthcare settings. This requirement is not about aesthetics; it is a direct safety measure designed to ensure accurate patient monitoring during anesthesia and throughout the operation. The nail bed provides a crucial, non-invasive window into the body’s internal oxygen balance. Any coating on the fingernail can obstruct this view, hindering the surgical team’s ability to maintain a safe environment for the patient.
The Critical Monitoring Tool
The primary device that mandates a clear fingernail is the pulse oximeter, a non-invasive instrument that provides continuous, real-time data on the patient’s oxygenation status. This device is typically clipped onto a fingertip or an earlobe and measures the saturation of oxygen in the blood, known as SpO2. This measurement is expressed as a percentage and indicates how well oxygen is being delivered to the body’s tissues.
The pulse oximeter functions by emitting two specific wavelengths of light—red light and infrared light—through the patient’s tissue. Oxygenated hemoglobin and deoxygenated hemoglobin absorb these wavelengths differently. Oxygenated hemoglobin absorbs more infrared light, while deoxygenated hemoglobin absorbs more red light. The device calculates the ratio of light absorption between the two wavelengths to determine the proportion of hemoglobin carrying oxygen. This provides the surgical team with an immediate assessment of the patient’s respiratory and circulatory function.
How Nail Coatings Interfere
Nail coatings, including traditional polish, gel manicures, and acrylics, interfere with pulse oximetry by physically and chemically disrupting the light transmission process. Darker shades, such as black, blue, green, and purple, contain pigments that absorb the light wavelengths emitted by the oximeter. This absorption mimics the light absorption pattern of deoxygenated blood, potentially leading to a falsely low oxygen saturation reading.
Thicker coatings, like gel, shellac, or acrylic nails, present a different challenge by physically scattering or obstructing the light beam. This physical barrier reduces the quality of the signal the sensor receives, which can cause the device to display an inaccurate or unreliable reading, or fail to register a reading at all. Some gel manicures have been shown to cause a false overestimation of oxygen saturation, which is dangerous. Even clear polish can sometimes cause issues due to its reflective properties.
The Safety Consequence of Impaired Monitoring
An impaired or inaccurate pulse oximetry reading directly jeopardizes patient safety by delaying the detection of hypoxia, a state of dangerously low oxygen levels in the blood. General anesthesia and certain medications administered during surgery can compromise a patient’s normal breathing patterns and reflexes. The surgical team relies on the oximeter’s early warning capability to identify this complication immediately.
If a nail coating causes the pulse oximeter to give a falsely normal reading, the surgical team may not realize the patient’s oxygen saturation is dropping in time to intervene. Conversely, a falsely low reading could lead to unnecessary interventions based on a misinterpretation of the patient’s true condition. In the operating room, where a patient’s oxygen level can drop rapidly, delayed or incorrect information can have serious consequences, including the risk of brain injury or cardiac arrest.
Alternatives and Practical Solutions
The simplest solution is for patients to remove all nail coatings from their fingers before arriving for a procedure. If a patient has permanent enhancements like acrylics or gels, removing the coating from at least one finger, typically the index finger, is required. Removing the coating from all ten fingers is the most secure approach to ensure no interference.
If a patient forgets or cannot remove the coating, the surgical staff will often attempt to use an alternative site for the pulse oximeter probe. Common alternative placements include the toe, earlobe, or a specialized adhesive sensor placed on the forehead. While these sites can provide an oxygen saturation measurement, the fingertip is the preferred and most reliable location for continuous monitoring. If staff must remove the polish upon arrival, this process can cause delays in the surgical schedule, making pre-operative preparation strongly encouraged.