Fig. 6.
The first detailed measurements of the blood volume pulsation with an oximeter and oximeter devices from the 1970s. (a) Schotz et al. documented the exact waveform of the blood volume pulse with oximeter measurements between 1958 and 1960 and demonstrated the physiological usefulness of this signal characteristic.142–144 Reprinted and modified from Schotz et al.,144 with permission from the publisher. (b), (c) Hewlett-Packard’s 47201A oximeter. Reprinted from Merrick,145 with permission from the publisher. (d) Skin reflectance oximeter developed by Cohen and Wadsworth; the first oximeter with light emitting diodes (LEDs).146 Reprinted from Cohen and Wadsworth,146 with permission from the publisher.