Pulse oximetry: an improved in vitro model that reduces blood flow-related artifacts

Abstract

Artifacts may occur in many in vitro models of pulse oximetry due to the optical effects of synchronously oriented and/or deformed erythrocytes. Although these artifacts are most likely negligible in living superficial tissues, they are demonstrated to have considerable influence on the calibration curve obtainable from the in vitro simulation of pulse oximetry in such models, especially at low oxygen saturations. Therefore, we have developed a modified in vitro model which reduces the effect of these artifacts. This is achieved by excluding data obtained during pressure transients and by raising the blood flow velocity. As a result, the model more closely approximates in vivo pulse oximetry, particularly under clinically important conditions of low blood oxygen saturation levels.

Development and testing of an artificial arterial and venous pulse oximeter

“…To perform a validation and calibration of the designed system, it was decided to perform an in-vivo animal test setup to compare the testing technique to that of other studies, including that of Aoyaki's in-vitro test setup (Edrich et al, 2000). However many physiological limitations were faced during animal experimentation, the results of which provided a testing base line but where ultimately inconclusive.…”

“…The in-vitro technique employed in this study was an expanded and modified version of that used in the studies performed and discussed by Edrich et al in 2000 [11]. The modified in-vitro setup consisted of two identical subcircuits, namely the arterial and venous simulating loops.…”

Secondary Transform Decoupling of Shifted Nonstationary Signal Modulation Components: Application to Photoplethysmography

“…Refs. [6][7][8][9]. Although pulse oximetry has been shown to be a reasonably accurate technique for the determination of oxygen saturation and heart rate, 10 Moyle 11 states that "the most important function of the plethysmogram in pulse oximetry is to assess whether the pulse oximeter is functioning correctly".…”

Virtual Instrument for the Measurement of Haemo-dynamic Parameters Using Photoplethysmograph

“…Pulse oximetry, first introduced by Takuo Aoyagi et al [5], provides continuous measurement of blood oxygen saturation and is an important medical technique for emergency, critical care and for everyday medical checkups. The values of PPG at systole and diastole are traditionally used for oxygen saturation measurements in a typical pulse oximeter [6][7][8][9][10][11].…”