Sentence:  Two technological advances, light-emitting diodes (LEDs) and microprocessors, plus the ingenious idea of analyzing the change in light absorption produced by arterial pulsations, resulted in the development of a new generation of <WSD>oximeters</WSD>: the pulse <WSD>oximeter</WSD> [...]. Now, clinicians are again thinking of oxygenation as a function of the degree of saturation and oxygen content, as the pulse <WSD>oximeter</WSD> becomes the preferred monitoring device. 
Meaning of the word marked with <WSD> tags:  A device that measures the oxygen saturation of arterial blood. (from 1942)<ref name="Brans & Hay"/>