Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: sensor attachment, wearable sensor, pulse oximetry, motion artifact, contact pressure, remote physiological monitoring. Includes bibliographical references (p.54-57).

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: wearable medical sensors; arterial oxygen saturation; software development; embedded systems; heart rate; respiration rate; heart rate variability; pulse oximetry; digital signal processing Includes bibliographical references (leaves 125-133).

Thesis (M.S.)--University of North Texas, Dec., 2007. / Title from title page display. Includes bibliographical references.

The ability of pulse oximeters to measure carboxyhemoglobin (HbCO) in blood or measure accurate values of oxygen saturation (SpO2) in the presence of elevated levels of HbCO is an important advantage because high exposure to carbon monoxide (CO) can be fatal or results in permanent neurological damage. The aim of my research was to develop an algorithm that would measure SpO2 and SpCO simultaneously using a pulse oximeter. Several specific wavelengths at which changes in SpCO and SpO2 can be measured with high sensitivity and specificity were identified. The choice of these wavelengths was experimentally verified utilizing an in-vitro set up. Preliminary results using our algorithm showed an accuracy of -1.1 to +2.7% [±1.96 SD] for SpO2 ranging between 70-100%, and -2 to 3.3% [±1.96 SD] for SpCO ranging between 30% with a specificity of 83.3% and a sensitivity of 100% for SpO2 and SpCO, respectively.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: Biome, pulse oximeter, wearable sensors, telemedicine. Includes bibliographical references (leaves 115-119 ).

Over the past decade, there has been an increasing interest in the real-time monitoring of ambulatory vital signs such as heart rate (HR) and arterial blood oxygen saturation (SpO2) using wearable medical sensors during field operations. These measurements can convey valuable information regarding the state of health and allow first responders and front-line medics to better monitor and prioritize medical intervention of military combatants, firefighters, miners and mountaineers in case of medical emergencies. However, the primary challenge encountered when using these sensors in a non-clinical environment has been the presence of persistent motion artifacts (MA) embedded in the acquired physiological signal. These artifacts are caused by the random displacement of the sensor from the skin and lead to erroneous output readings. Several signal processing techniques, such as time and frequency domain segmentation, signal reconstruction techniques and adaptive noise cancellation (ANC), have been previously developed in an offline environment to address MA in photoplethysmography (PPG) with varying degrees of success. However, the performance of these algorithms in a spasmodic noise environment usually associated with basic day to day ambulatory activities has still not been fully investigated. Therefore, the focus of this research has been to develop novel MA algorithms to combat the effects of these artifacts. The specific aim of this thesis was to design two novel motion artifact (MA) algorithms using a combination of higher order statistical tools namely Kurtosis (K) for classifying 10 s PPG data segments, as either ‘clean’ or ‘corrupt’ and then extracting the aforementioned vital parameters. To overcome the effects of MA, the first algorithm (termed ‘MNA’) processes these ‘corrupt’ PPG data segments by identifying abnormal amplitudes changes. The second algorithm (termed ‘MNAC’), filters these ‘corrupt’ data segments using a 16th order normalized least mean square (NLMS) ANC filter and then extracts HR and SpO2.

Over the past decade, there has been an increasing interest in the real-time monitoring of ambulatory vital signs such as heart rate (HR) and arterial blood oxygen saturation (SpO2) using wearable medical sensors during field operations. These measurements can convey valuable information regarding the state of health and allow first responders and front-line medics to better monitor and prioritize medical intervention of military combatants, firefighters, miners and mountaineers in case of medical emergencies. However, the primary challenge encountered when using these sensors in a non-clinical environment has been the presence of persistent motion artifacts (MA) embedded in the acquired physiological signal. These artifacts are caused by the random displacement of the sensor from the skin and lead to erroneous output readings. Several signal processing techniques, such as time and frequency domain segmentation, signal reconstruction techniques and adaptive noise cancellation (ANC), have been previously developed in an offline environment to address MA in photoplethysmography (PPG) with varying degrees of success. However, the performance of these algorithms in a spasmodic noise environment usually associated with basic day to day ambulatory activities has still not been fully investigated. Therefore, the focus of this research has been to develop novel MA algorithms to combat the effects of these artifacts. The specific aim of this thesis was to design two novel motion artifact (MA) algorithms using a combination of higher order statistical tools namely Kurtosis (K) for classifying 10 s PPG data segments, as either ‘clean’ or ‘corrupt’ and then extracting the aforementioned vital parameters. To overcome the effects of MA, the first algorithm (termed ‘MNA’) processes these ‘corrupt’ PPG data segments by identifying abnormal amplitudes changes. The second algorithm (termed ‘MNAC’), filters these ‘corrupt’ data segments using a 16th order normalized least mean square (NLMS) ANC filter and then extracts HR and SpO2.

Thesis (M.S.)--West Virginia University, 2003 / Title from document title page. Document formatted into pages; contains viii, 96 p. : ill. (some col.) Includes abstract. Includes bibliographical references (p. 72-74).

Thesis (MScIng)--Stellenbosch University, 2008. / ENGLISH ABSTRACT: Conventional pulse oximetry has limited accuracy in measuring blood oxygen saturation in low saturation and perfusion scenarios. This limits the application of pulse oximetry in patients su ering from peripheral vascular a ictions. A novel pulse oximetry system is presented in this study which proposes solutions to these low saturation and perfusion issues. The presented system was designed to overcome the low perfusion issues by inducing an arti cial pulse in the detected photoplethysmograph. A novel arterio-venous hypothesis was formulated to extract arterial and venous saturation data from this arti cial photoplethysmograph using arterial-to-venous compliance ratios. Sensor wavelengths were selected to provide high and low saturation accuracy, followed by an in vitro sensor calibration procedure. System performance was validated by means of in vivo human studies. In vivo results indicate good accuracy for high saturation, with limited accuracy in low saturation scenarios. The arterio-venous hypothesis was validated, indicating that venous saturation information can be extracted from the arti cial PPG. Although inconclusive, results indicate that the proposed system might be able to accurately monitor arterial and venous saturation in severe hypoperfusion scenarios with recommended hardware and calibration modi cations. It is recommended that further studies into the presented system's performance are conducted. / AFRIKAANSE OPSOMMING: Konvensionele 'pulse oximetry' sisteme het beperkte akkuraatheid tydens die meting van bloed suurstof saturasie in lae saturasie en perfusie gevalle. Dit beperk die bruikbaarheid van 'pulse oximetry' in pasiënte wat ly aan perifere vaskulêre siektes. 'n Nuwe 'pulse oximetry' sisteem, wat oplossings vir hierdie lae saturasie en perfusie beperkings voorstel, word in hierdie studie aangebied. Die voorgestelde sisteem is ontwerp om die lae perfusie beperkings te oorkom deur 'n kunsmatige polsslag in die 'photoplethysmograph' te induseer. 'n Nuwe arterio-veneuse hipotese is geformuleer om arteriële en veneuse saturasie inligting uit hierdie kunsmatige polsslag te onttrek deur middel van 'n arteriële-teenoor-veneuse styfheids verhouding. Die gol engtes wat gebruik is in die sensors, is spesi ek gekies om hoë en lae saturasie akkuraatheid te verskaf. 'n In vitro kalibrasie prosedure is gevolg om die sensors vir hoë en lae saturasie te kalibreer, waarna die werkverrigting van die sisteem getoets is deur middel van 'n in vivo validasie prosedure. Die in vivo resultate toon goeie akkuraatheid vir hoë saturasie, met beperkte akkuraatheid vir lae saturasie. Die arterio-veneuse hipotese is gevalideer, wat aandui dat veneuse saturasie wel uit die kunsmatige 'photoplethysmograph' onttrek kan word. Alhoewel die resultate wat in hierdie studie aangebied word nie omvattend of beslissend is nie, dui dit egter aan dat die voorgestelde sisteem dalk in staat kan wees om arteriële en veneuse saturasie in uiters lae perfusie gevalle te meet. Verbeteringe sal egter aan die sisteem aangebring moet word in terme van hardeware en kalibrasie, om 'n meer gestandardiseerde metings metode te verseker. Verdere navorsing oor die werkverrigting van die voorgestelde sisteem word ook voorgestel.

Noninvasive pulse oximetry represents an area of potential interest to the army, because it could provide cost-effective, safe, fast and real-time physiological assessment in a combat injured soldier. Consequently, there is a need to develop a reliable, battery-powered, wearable pulse oximeter to acquire and process photoplethysmographic (PPG) signals using an optimized sensor configuration. A key requirement in the optimal design of a wearable wireless pulse oximeter is low power management without compromising signal quality. This research investigated the advantage gained by increasing the area of the photodetector and decreasing the light emitting diode (LED) driving currents to reduce the overall power requirement of a reflectance mode pulse oximeter sensor. In vitro and preliminary in vivo experiments were conducted to evaluate a multiple photodetector reflectance sensor setup to simulate a varying detection area. It was concluded that a reflection pulse oximeter sensor employing a large area photodetector is preferred over a similar transmission type sensor for extending the battery life of a wireless pulse oximeter intended for future telemedicine applications.