The requirement to remove nail polish before surgery is a common mandate across hospitals worldwide. This rule is not based on aesthetics or policy alone; it is a fundamental safety measure linked to a patient’s well-being while under anesthesia. The primary concern revolves around the potential for nail coatings to interfere with routine patient monitoring. This specifically affects the accurate assessment of how well the body is handling oxygen during the operation. Ensuring precise patient data allows the surgical team to make rapid, informed decisions that prevent serious complications.
The Essential Role of Pulse Oximetry
Monitoring oxygen saturation in the blood is a necessary procedure during any surgery that involves general anesthesia or heavy sedation. Anesthetic agents and pain medications can suppress the body’s natural drive to breathe, leading to reduced ventilation and a potential drop in blood oxygen levels, a condition known as hypoxemia. The patient monitoring device used to detect this issue is the pulse oximeter, a small, clip-like probe that is typically placed on a finger or an earlobe.
The pulse oximeter provides continuous, non-invasive feedback on the percentage of hemoglobin in the arterial blood that is saturated with oxygen, which is displayed as a SpO2 reading. This reading is a near-instantaneous indicator of oxygen delivery to the body’s peripheral tissues. By constantly assessing this value, the anesthesia team receives an early warning sign if the patient is not receiving or distributing adequate oxygen, allowing for immediate intervention before a crisis develops.
How Polish Disrupts Oxygen Readings
The physics behind the pulse oximeter explains why nail polish is problematic. The device operates on the principle of spectrophotometry, shining two specific wavelengths of light through the fingertip tissue. These two light sources are absorbed differently by oxygenated hemoglobin and deoxygenated hemoglobin, allowing the machine to calculate the ratio between the two.
Pigments found in nail polish, particularly dense or dark colors such as deep blue, black, green, or purple, can absorb light at or near the wavelengths used by the oximeter. This chemical interference effectively blocks or alters the light signal before it can reach the sensor, skewing the absorption data. This interference often causes the machine to calculate a falsely low oxygen saturation reading. Conversely, the polish can sometimes block the signal entirely, resulting in no reading at all. Gel-based polishes can also cause issues, occasionally leading to an unreliable high reading, masking a true oxygen deficiency.
Beyond the Machine: Visual Checks and Infection Control
Visual Assessment
While interference with the pulse oximeter is the primary reason, a second layer of safety involves the surgical team’s ability to visually assess the patient. The nail bed is a location where the color of the underlying tissue and blood flow can be quickly checked. A normal, healthy nail bed should have a pinkish tint due to good circulation and oxygenation. If the patient’s oxygen levels drop significantly, the blood in the capillaries under the nail bed can take on a bluish or purplish hue, a clinical sign known as cyanosis. This visual cue is a fast, independent confirmation of a problem that a physician can spot instantly.
Infection Control Risk
The requirement also extends to artificial nails, such as acrylics and gels, which introduce a separate infection control risk. Artificial nails, especially when they are long or have micro-fissures, are known to harbor a higher concentration of pathogenic microorganisms, including Gram-negative bacteria and yeasts. These microbes are difficult to eliminate even with vigorous surgical hand scrubbing. This heightened microbial load increases the chance of bacteria shedding into the sterile surgical field, elevating the risk of a surgical site infection for the patient.