| Pulse-oximetry technology was available in 1930's it | | | | Pulse oximetry is a non-invasive and continuous |
| became easily available only in the 1980's with | | | | method of determining the amount of oxygenated and |
| advances in the Light Emitting Diode (LED), | | | | deoxygenated hemoglobin in a person's blood supply. |
| microprocessors, optical plethysmography and | | | | A pulse oximeter is a particularly convenient |
| spectro-photometry. Today pulse-oximetry provides a | | | | noninvasive and measurement instrument. It has a pair |
| simple, non-invasive, portable and inexpensive method | | | | of small light-emitting diodes (LEDs) facing a |
| to continuously monitor oxygen saturation and heart | | | | photodiode through a translucent part of the patient's |
| rate with good accuracy. | | | | body, usually a fingertip or an earlobe. One LED is red, |
| A pulse oximeter is a particularly convenient | | | | with wavelength of 660 nm, and the other is infrared, |
| noninvasive and measurement instrument. It has a pair | | | | 905, 910, or 940 nm. Absorption at these wavelengths |
| of small light-emitting diodes (LEDs) facing a | | | | differs significantly between oxyhemoglobin and its |
| photodiode through a translucent part of the patient's | | | | deoxygenated form, therefore from the ratio of the |
| body, usually a fingertip or an earlobe. One LED is red, | | | | absorption of the red and infrared light the oxy |
| with wavelength of 660 nm, and the other is infrared, | | | | deoxyhemoglobin ratio can be calculated. The |
| 905, 910, or 940 nm. Absorption at these wavelengths | | | | absorbance of oxyhemoglobin and deoxyhemoglobin |
| differs significantly between oxyhemoglobin and its | | | | is the same (isosbestic point) for the wavelengths of |
| deoxygenated form, therefore from the ratio of the | | | | 590 and 805 nm; earlier oximeters used these |
| absorption of the red and infrared light the oxy | | | | wavelengths for correction for hemoglobin |
| deoxyhemoglobin ratio can be calculated. The | | | | concentration. |
| absorbance of oxyhemoglobin and deoxyhemoglobin | | | | Uses of pulse oximetry- |
| is the same (isosbestic point) for the wavelengths of | | | | - This helps clinician in |
| 590 and 805 nm; earlier oximeters used these | | | | - Noninvasive arterial oxygen saturation monitoring. |
| wavelengths for correction for hemoglobin | | | | - Pulse rate monitoring. |
| concentration. | | | | |