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By Madeline Pittman


CMS pulse oximeters are applicances applied in pulse oximetry. This sort of oximetry is a suitable technique for assessing levels of saturation of oxygen in human body because it is noninvasive. The device was invented around 1940s by a physician named Allan Millikan Glenn. The first appliance operated with 2 wavelengths and used to be placed on ears. The two wave-lengths were in form of green and red filters.

This original model was later improved by some physician called Wood in 1949. Wood incorporated a pressure capsule for squeezing blood out of the ear to get zero setting in an attempt to get absolute Oxygen saturation level. The present models work on the same principals as the original one. The working principal was however difficult to implement due to unstable light sources and photocells.

Oximetry itself was initially developed in 1972 at Nihon Kohden by two bioengineers, Aoyagi and Kishi. These two utilized the ratio of infrared to red light absorption of pulsating constituents at measuring sites. Commercial distribution of oximeter happened in the year 1981 through a firm called Biox. By then, the device was majorly utilized in operating rooms and firms that produced it concentrated most of their advertising in the same direction.

Oximetry is a crucial noninvasive technique of determining the amount of oxygen in human body. It utilizes a pair of small LEDS, light emitting diodes, which face some photodiode through a translucent portion of the body. Examples of such translucent parts are fingertips, earlobes, and toe tips. One LED is red whereas the other is infrared. The red LED is usually 660 nm while the infrared LED is 940, 910, or 905 nm.

The absorption speed of the 2 wavelengths differs between oxygenated and deoxygenated versions of oxygen in human body. This disparity in rate of absorption may be utilized to gauge the ratio between de-oxygenated and oxygenated blood oxygen. The indicated signal is changed over time with each heartbeat since arterial blood veins constrict and expand with each passing heartbeat. The monitors are capable of assuming other tissues or makeup on nails by monitoring the varying portion of absorption spectrum alone.

By observing the varying absorption section alone, the blood oxygen monitor only displays the percentage of arterial hemoglobin in oxyhemoglobin configuration. Patients without COPD but with hypoxic drive issues have a reading that ranges between 95 and 99 percent. Those with hypoxic drive issues normally have values that range between 88 and 94 percent. Usually figures of 100 percent may suggest carbon monoxide poisoning.

An oximeter is usable in many environments and applications where oxygenation of a person is unstable. Among the major environments of use consist of ward and hospital settings, surgical rooms, cockpits in un-pressurized airplane s, recovery units, and intensive care units. The disadvantage of these equipment is that it can only measure the percentage of saturation of blood hemoglobin and not ventilation. Hence therefore, it is not a full evaluation of respiratory sufficiency.

CMS pulse oximeters are made in several varieties. Some are inexpensive costing a few dollars whereas others are very sophisticated and expensive. They may be purchased from any shop that stocks such pieces of equipment.




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