The requirement to remove artificial nails or nail polish before surgery is tied directly to patient safety. This is not about sterility or appearance policies, but the surgical team’s ability to accurately monitor oxygen levels under anesthesia. A covering on the nail bed can obscure the device that provides immediate, life-saving information.
The Critical Monitoring Tool
Clear nails are required because of the pulse oximeter, a device routinely used in all surgeries involving anesthesia. This non-invasive monitor clips onto a fingertip and uses light to measure the percentage of oxygen saturation in the blood. It shines two different wavelengths of light, typically red and infrared, through the finger tissue.
A sensor on the opposite side of the finger measures how much of each light wavelength passes through the blood and tissue. Oxygenated blood absorbs light differently than deoxygenated blood, allowing the oximeter to calculate the oxygen saturation level. Even small changes in this reading provide the surgical team with an early warning sign of potential breathing or circulation issues.
Restrictions on Artificial Nail Coverings
Any material that blocks or absorbs the light emitted by the pulse oximeter can lead to a falsely low or an unreliable reading. This interference is the primary reason why most hospitals require the removal of nail coverings before surgery. The thickness and opacity of acrylic, gel, or dip powder nails create a physical barrier that the oximeter’s light struggles to penetrate effectively.
The chemical composition of dark or metallic nail polish is also problematic because the pigments absorb the light wavelengths used by the device. Specifically, colors like black, dark blue, green, and purple have been shown to significantly interfere with the sensor’s ability to get an accurate reading. The standard of care is to eliminate all potential variables that could compromise monitoring, even though some studies suggest the inaccuracy may not be clinically significant in healthy individuals.
Gel and shellac polishes present a unique issue because of their difficulty in quick removal. If an emergency occurs during surgery and the monitor’s reading is questionable, the surgical team may need to rapidly remove the polish to confirm the reading or to visually check the nail bed for signs of cyanosis, a bluish tint indicating low oxygen. The hardness of these cured polishes makes them impossible to remove quickly with standard acetone, posing a risk of delayed response. Clear nails are preferred because the nail bed is one of the quickest places for the surgical team to visually detect changes in oxygenation.
Pre-Operative Preparation and Alternatives
Patients are asked to remove all nail polish, gel, and artificial nails before arriving at the surgical facility. The minimum requirement is usually to have at least one finger on each hand completely clear. Since the index finger is the most common site for the pulse oximeter, clearing this digit on both hands is often sufficient if you cannot remove all artificial nails.
If a fake nail cannot be removed before the procedure, the surgical team has alternative sites for monitoring oxygen saturation. The pulse oximeter probe can often be placed on the patient’s earlobe or a toe instead of the finger. While these alternatives are readily available, the fingertip is the preferred and most reliable location for routine monitoring.
In some cases, a different type of sensor, such as a reflectance sensor, may be used on the forehead, especially if peripheral circulation is compromised. However, the default expectation is that the patient will follow the pre-operative instructions to clear the fingernails, ensuring the most accurate and easily accessible monitoring site is available from the start.