Description and Technology
Pulse oximeters are medical devices that measure the pulse rate and the amount of oxygen saturation of the blood. More specifically, they measure the arterial oxygen saturation of the hemoglobin, a blood protein that carries oxygen throughout your system. Oximeters work with a technology called spectrophotometry. This process emits light from an oximeter and measures the transmission and absorption of the light by the hemoglobin in your blood. A microprocessor in the device uses this information to calculate your pulse and oxygen saturation. In order for the light to reach your blood, the oximeter is attached to a relatively translucent part of your body with good blood flow, such as your finger. This procedure is instantaneous, painless and noninvasive.
Oxygen Saturation
The goal of breathing and blood circulation is to deliver oxygen to all areas of the body. Oxygen is carried in your blood by the protein hemoglobin, which chemically binds oxygen molecules to itself. Each molecule of hemoglobin is capable of carrying four molecules of oxygen.
Oxygen saturation is the quantity of hemoglobin that is carrying oxygen versus the total amount of hemoglobin in your blood. Normal levels of oxygen saturation are 95 to 100 percent depending on your age. This means that 95 to 100 percent of all available hemoglobin in your blood should be carrying oxygen. Any reading below 90 percent can lead to life-threatening complications. Certain factors can cause a decrease in your oxygen saturation such as high altitudes, disease, aging, carbon monoxide poisoning and a traumatic injury. Low levels of oxygen saturation indicate that you are hypoxic (oxygen starved) and require medical treatment and supplemental oxygen.
Practical Uses
According to the World Federation of Societies of Anesthesiologists, pulse oximetry is used extensively in emergency care, intensive care and critical care areas of clinical environments. Pulse oximeters are employed to monitor patients who have potential or actual respiratory problems. The safe, simple, portable and noninvasive features of the oximeter make it a versatile and accurate monitor in a variety of health care settings. Oximeters are used to check the cardio-respiratory status of neonates, patients undergoing surgery, during emergency transport, in ICU units, postoperatively and more.
References
- Fundamentals of Respiratory Care; Robert L. Wilkins et al.; 2009
- Respiratory Care Journal
- World Federation of Societies of Anaesthesiologists
