The instruction to remove nail polish before surgery is a standard precaution directly related to patient well-being. This requirement is enforced because maintaining an accurate, continuous stream of physiological data is paramount for safely managing a patient under anesthesia or sedation. Any covering on the fingernails can interfere with the medical devices and observational checks used to monitor the body’s fundamental life support functions.
The Role of the Pulse Oximeter
The primary reason for clear nails centers on the function of the pulse oximeter. This non-invasive monitor is routinely clipped onto a finger, earlobe, or toe. The device provides a continuous measurement of peripheral oxygen saturation (SpO2), which reflects the percentage of hemoglobin in the blood carrying oxygen. This reading gives the anesthesia team immediate feedback on how efficiently the patient is breathing and circulating oxygen.
The pulse oximeter calculates this value without drawing blood by shining two distinct wavelengths of light—red and infrared—through the tissue. These specific wavelengths are used because oxygenated and deoxygenated hemoglobin absorb light differently. Oxygen-rich blood absorbs more infrared light while allowing more red light to pass through.
Conversely, blood lacking oxygen absorbs more red light and permits more infrared light to transmit. By measuring the ratio of light absorption, the device rapidly computes the oxygen saturation level. Monitoring this value is important during surgery, especially when respiration is controlled by mechanical ventilation, as it allows for the earliest possible detection of a drop in blood oxygenation. Early identification is necessary for staff to intervene quickly.
How Nail Coverings Block Monitoring
Nail polish, gel manicures, and acrylic overlays interfere with the pulse oximeter by physically blocking the light transmission path. The chemical pigments and physical thickness of the covering absorb or scatter the red and infrared light beams before they reach the detector. This interference corrupts the light ratio calculation the oximeter relies on to determine the SpO2 value.
Studies show that darker shades like black, blue, green, and purple cause the most significant distortion to readings. These pigments absorb the light wavelengths strongly, leading to inaccurate or falsely low oxygen saturation values. Thick applications, such as gel or dip manicures, also present a problem even if the color is light, due to the physical barrier they create. The presence of any covering introduces uncertainty that medical personnel cannot accept when tracking a patient’s breathing status.
Secondary Reasons for Clear Nails
Beyond electronic monitoring, the natural nail bed provides a quick, visual assessment tool for observing a patient’s circulatory health. The color of the tissue beneath the fingernail is an early indicator of perfusion and oxygen status. In an emergency, a healthcare provider can quickly press on the nail bed to perform a capillary refill test, noting how quickly the pink color returns once pressure is released.
A bluish tint to the nail bed, known as cyanosis, is a physical sign that the blood is not adequately oxygenated. Nail polish or artificial nails entirely conceal this visual cue, delaying the recognition of a drop in oxygen levels. This visual check is a simple, immediate confirmation of electronic monitor readings, adding a layer of safety that polish obstructs.
Artificial nails, including acrylics and gels, also pose a separate safety concern related to infection control. These coverings can create tiny spaces that harbor bacteria and other microorganisms between the natural and artificial material. A sterile environment is paramount in the operating room, and any item that increases the risk of contamination, particularly surgical site infections, must be removed.
Pre-Surgery Preparation and Removal Policy
Patients must remove all nail products from their fingers before arriving at the surgical facility to ensure the procedure proceeds without delays. This includes regular polish, gel manicures, shellac, and artificial nails, as removal is time-consuming and often cannot be accommodated by staff on the day of surgery. While some facilities may permit one finger (typically the index finger) to have the product removed, most policies require all nails to be completely clear for flexibility in monitoring site placement.
If a patient arrives with nail polish, the surgical team may use an alternative monitoring site, such as the earlobe or a toe, which can provide a less optimal reading. Staff may also need to physically remove the polish using acetone, which can delay the start of the operation. Even clear or nude-colored polishes must be removed, as their composition or thickness can still interfere with the light-based monitoring technology.