Pulse oximetry is the monitoring of oxygen concentration in the blood. Initially, pulse oximeters were only used in critical care settings, such as monitoring for hypoxia in patients undergoing general anesthesia or under a ventilator. Pulse oximeters are now used both in hospital settings and in the home. They provide a non-invasive and painless way to determine oxygen levels in the blood. This allows blood oxygen levels to be measured multiple times or continuously without needing to obtain a blood sample. They can be used by patients with diseases that affect their oxygen levels. They can also be used by athletes who wish to monitor their heart rate and oxygen levels during exercise. An abnormal oxygen level or heart rate may be the first alert that someone needs medical attention, and pulse oximeters can provide a quick assessment.
How Does a Pulse Oximeter Work?
Hemoglobin is a component of red blood cells, which carry oxygen to the organs in your body. Hemoglobin carrying oxygen, or oxygenated hemoglobin, gives off different light wavelengths compared to deoxygenated hemoglobin. Pulse oximeters estimate the level of oxygenation in the blood by measuring the differences in light wavelengths given off by oxygenated and deoxygenated hemoglobin. Pulse oximeters contain 2 LED (light-emitting diode) probes, an infrared light probe and a red light probe. The probe is attached to a finger or earlobe. The pulse oximeter emits infrared light which is then absorbed by oxygenated hemoglobin. Red light is absorbed by deoxygenated hemoglobin. The degree of light absorption varies according to the amount of oxygenation in the blood. The pulse oximeter converts this information to a percentage of hemoglobin saturation, known as SpO2.
What Can You Learn From a Pulse Oximeter
A pulse oximeter can reveal the SpO2, or oxygen saturation of hemoglobin and the pulse rate. Any deviation from a person's baseline or deviation from the normal levels may indicate that there is an issue with cardiac output, lung ventilation, or oxygen delivery to tissues. Normal oxygen saturation in arterial blood, or blood that is pumped from the heart to the tissues, is above 95%. A drop in oxygen levels can occur in pneumonia, suffocation, heart failure, sleep apnea, emphysema, or lung cancer. A pulse oximeter can indicate whether someone needs evaluation for disorders of the lung, heart, or blood vessels. In the hospital setting, patients receiving respiratory support can use pulse oximetry to determine whether ventilator settings need to be adjusted. People with chronic need for oxygen supplementation such as sleep apnea and chronic obstructive pulmonary disease (COPD) can use pulse oximetry to adjust oxygen supplementation levels. Pulse oximeters can also monitor pulse rate for people with certain heart conditions or taking medications that may affect their heart rate.
Personal Pulse Oximeters
Personal pulse oximeters are inexpensive, easy to use, and can be helpful in monitoring oxygen levels and heart rates at home. This is especially relevant for people with chronic lung or heart conditions that may affect their oxygen levels. Fingertip pulse oximeters are widely available in pharmacies and various online marketplaces. Some fingertip pulse oximeters can even store data that can later be reviewed by a physician to monitor the effectiveness of oxygen therapies and the need to adjust treatment. Personal pulse oximeters are portable and can be used any time, whether at home, sleeping, or outside the home doing social activities. Pulse oximeters can be used as needed, while some types can be attached to the finger and provide continuous monitoring. Another type is the ear-clip pulse oximeter for people who cannot use fingertip pulse oximeters, such as diabetics who have poor blood circulation in their fingers and toes. Athletes can use pulse oximeters to see their body's response to exercise regimens. People training in high altitudes may find it necessary to monitor their oxygen levels to ensure that the tissues receive enough oxygen from the blood.