The requirement to remove nail polish before surgery is a common instruction given to patients across all medical facilities. This request is not about hygiene or aesthetics but is a direct mandate for patient safety during the operation. The reason for this strict rule lies in the medical team’s ability to monitor a patient’s physiological status while under anesthesia. Any coating on the fingernails can interfere with monitoring equipment used throughout the procedure, making compliance a non-negotiable step.
Monitoring Oxygen Levels: The Role of the Pulse Oximeter
The medical device at the center of this requirement is the pulse oximeter, a non-invasive tool that continuously measures functional oxygen saturation (SpO2) in the blood. This device typically clips onto a fingertip and utilizes an electronic processor and two light-emitting diodes (LEDs). The LEDs emit specific wavelengths of light—red light and infrared light—through the tissue.
A sensor on the opposite side of the finger detects the light that passes through. Oxygenated hemoglobin absorbs the infrared light differently than deoxygenated hemoglobin. The oximeter uses the measured ratio of light absorption at these two wavelengths to calculate the percentage of hemoglobin carrying oxygen. This provides the surgical team with real-time information about the patient’s respiratory function.
Colored pigments in standard nail polish, particularly dark or opaque shades, absorb or scatter the emitted light before it reaches the sensor. This interference prevents the correct amount of light from reaching the detector, leading to a distorted or failed signal. Studies have shown that certain colors can cause an artificial decrease in the reading. An inaccurate reading could result in a dangerous delay in recognizing a true drop in oxygen levels while the patient is under general anesthesia.
Addressing Nail Enhancements: Gels, Acrylics, and Tips
Semi-permanent nail enhancements like gel polish, acrylic nails, and artificial tips present an even greater challenge than standard lacquer. These materials are applied in thicker layers, are often more opaque, and act as a substantial physical barrier to the light beams. The thickness of the enhancement can impede the passage of light, making it difficult for the sensor to detect a signal.
The components in gel polish may react differently with the light wavelengths than standard polish. Certain colors of gel polish can cause a false overestimation of the oxygen saturation reading. This is hazardous because a falsely high reading can mask the early signs of hypoxemia (a dangerously low level of oxygen in the blood), delaying intervention.
Unlike traditional polish, which can be wiped off quickly, gel and acrylic enhancements require a specialized, time-consuming removal process. This process often involves prolonged soaking in acetone or filing the material down. Since this cannot be performed rapidly by surgical staff in an emergency, these enhancements must be removed before the patient arrives. A clear, natural nail bed is required for all cosmetic coverings.
Ensuring Safety: Pre-Surgical Preparation Steps
To eliminate any risk of interference, medical facilities require that all fingernails and toenails be completely free of any coatings. The safest approach is to remove all polish well in advance of the scheduled surgery, even clear coats. This proactive step ensures reliable physiological monitoring from the moment the patient is connected to the equipment.
The fingertip is the preferred site for the pulse oximeter due to its accessibility and high blood flow, which is necessary for a strong signal. However, surgical teams recognize scenarios where the finger is unavailable, such as trauma or poor peripheral circulation.
In these situations, alternative monitoring sites can be utilized. Specialized probes can be placed on the earlobe, the toe, or the forehead, as these areas also contain sufficient blood flow for accurate readings. While alternative sites provide a necessary backup, the finger remains the primary choice for continuous, reliable monitoring. Removing nail polish is a direct safety measure integrated into the standard of care for any procedure involving anesthesia or sedation.