A<unk> imeter probe applied to a person's finger A<unk> imeter is a medical device that indirectly monitors the oxygen saturation of a patient's blood (as opposed to measuring oxygen saturation directly through a blood sample) and changes in blood volume in the skin, producing a photoplethysmogram that may be further processed into other measurements. The<unk> imeter may be incorporated into a multiparameter patient monitor. Most monitors also display the<unk>  rate.<unk> rtable, battery-operated<unk> imeters are also available for transport or home blood-oxygen monitoring. Advantages<unk>  is particularly convenient for noninvasive continuous measurement of blood oxygen saturation. In contrast, blood gas levels must otherwise be determined in a laboratory on a drawn blood sample.<unk>  is useful in any setting where a patient's oxygenation is unstable, including intensive care, operating, recovery, emergency and hospital ward settings, pilots in unpressurized aircraft, for assessment of any patient's oxygenation, and determining the effectiveness of or need for supplemental oxygen. Although a<unk> imeter is used to monitor oxygenation, it cannot determine the metabolism of oxygen, or the amount of oxygen being used by a patient. For this purpose, it is necessary to also measure carbon dioxide (CO2) levels. It is<unk> ssible that it can also be used to detect abnormalities in ventilation. However, the use of a<unk> imeter to detect hypoventilation is impaired with the use of supplemental oxygen, as it is only when patients breathe room air that abnormalities in respiratory function can be detected reliably with its use. Therefore, the routine administration of supplemental oxygen may be unwarranted if the patient is able to maintain adequate oxygenation in room air, since it can result in hypoventilation going undetected. Because of their simplicity of use and the ability to provide continuous and immediate oxygen saturation values,<unk> imeters are of critical importance in emergency medicine and are also very useful for patients with respiratory or cardiac problems, especially COPD, or for diagnosis of some sleep disorders such as apnea and hypopnea. For patients with obstructive sleep apnea,<unk>  readings will be in the 70–90% range for much of the time spent attempting to sleep.<unk> rtable battery-operated<unk> imeters are useful for pilots operating in non-pressurized aircraft above or in the U.S. where supplemental oxygen is required.<unk> rtable<unk> imeters are also useful for mountain climbers and athletes whose oxygen levels may decrease at high altitudes or with exercise. Some<unk> rtable<unk> imeters employ software that charts a patient's blood oxygen and<unk> , serving as a reminder to check blood oxygen levels. Connectivity advancements have made it<unk> ssible for patients to have their blood oxygen saturation continuously monitored without a cabled connection to a hospital monitor, without sacrificing the flow of patient data back to bedside monitors and centralized patient surveillance systems. For patients with COVID-19,<unk>  helps with early detection of silent hypoxia, in which the patients still look and feel comfortable, but their<unk>  is perilously low. This happens to patients either in the hospital or at home. Low<unk>  may indicate severe COVID-19-related pneumonia, requiring a ventilator.
Pulse oximetry
Plethysmograph
Oxygenation index
Hyperoxia test
Oxygen saturation 
Oxygen saturation
Fraction of inspired oxygen
Respiratory pressure meter