oxímetro

An oxímetro, commonly called a pulse oximeter, is a noninvasive medical device that estimates the oxygen saturation of a person’s blood, expressed as SpO2, and heart rate. It is usually worn on a finger, toe, or earlobe and uses light-emitting diodes and a photodetector to measure the relative amounts of oxygenated and deoxygenated hemoglobin.

By emitting red and infrared light and analyzing how much light is absorbed, the device provides a numerical SpO2 value and a pulse rate. Normal SpO2 in healthy individuals typically falls around 95% to 100%, though values below 92% may require medical evaluation, especially in people with lung or heart conditions.

Pulse oximeters are widely used in hospitals, clinics, ambulatory care, and at home for monitoring during anesthesia, sleep studies, respiratory illnesses, and altitude exposure. They are also used in sports and aviation contexts.

Several factors can affect accuracy, including poor peripheral perfusion, cold extremities, movement, nail polish or artificial nails, skin pigmentation, ambient light, and the presence of abnormal hemoglobins. They do not measure ventilation or carbon dioxide levels and can be misleading in certain conditions such as methemoglobinemia or carbon monoxide poisoning.

Devices come in finger clip, handheld, and pediatric forms, and some wearables integrate oximetry sensors into wristwatches. Users should follow manufacturer guidance, ensure proper fit, keep sensors clean and dry, and recognize that oximetry is a noninvasive estimate rather than a definitive arterial blood gas measurement.