Investigation of photoplethysmographic signals and blood oxygen saturation values on healthy volunteers during cuff-induced hypoperfusion using a multimode PPG/SpO2 sensor

Photoplethysmography (PPG) is a technique widely used to monitor volumetric blood changes induced by cardiac pulsations. Pulse oximetry uses the technique of PPG to estimate arterial oxygen saturation values (SpO2). In poorly perfused tissues, SpO2 readings may be compromised due to the poor quality of the PPG signals. A multimode finger PPG probe that operates simultaneously in reflectance, transmittance and a combined mode called “transreflectance”’ was developed, in an effort to improve the quality of the PPG signals in states of hypoperfusion. Experiments on 20 volunteers were conducted to evaluate the performance of the multimode PPG sensor and compare the results with a commercial transmittance pulse oximeter. A brachial blood pressure cuff was used to induce artificial hypoperfusion. Results showed that the amplitude of the transreflectance AC PPG signals were significantly different (p\0.05) than the AC PPG signals obtained from the other two conventional PPG sensors (reflectance and transmittance). At induced brachial pressures between 90 and 135 mmHg, the reflectance finger pulse oximeter failed 25 times (failure rate 42.2 %) to estimate SpO2 values, whereas the transmittance pulse oximeter failed 8 times (failure rate 15.5 %). The transreflectance pulse oximeter failed only 3 times (failure rate 6.8 %) and the commercial pulse oximeter failed 17 times (failure rate 29.4 %)

Detection and classification real-time of fall events from the daily activities of human using forward scattering radar

Detection and identification of various human activities that have concurrently performed by two individuals or more is a crucial task of elderly assisted living systems. Fall is the biggest problem which may threaten the older people's life aged 65 and above, therefore, the real-time detection of human activities and classification of fall events is required whether in their houses or in the health care institutions. This paper presents a Forward Scattering Radar as a monitoring sensor for the real-time categorizing features of falls from the non-fall activities. The spectrogram representations are utilized for analyzing motion characteristics, while, based on the short-time Fourier transform features, the support vector machine has been used for classification operations. An indoor experiment was carried out to emulate the sitting on a chair of the older and forward falling down event, where 50 trials were fulfilled by 5 adults for each activity. The analysis results indicated that the Forward Scattering Radar has a pretty good ability in detecting of the daily activities and classification of fall from the different overlapping activities. The preliminary classification results have revealed a noticeable classification performance of the fall event when the two activities, the forward falling and sitting on a chair, are happened simultaneously

Human activities detection and classification based on micro-Doppler signatures near the baseline of forward scattering radar

Fall poses a major problem, which raises the concern of elderly populations aged 65 and above in all over the world. In this paper, we propose Forward Scattering Radar system as a Doppler sensor in distinguishing features of fall events from non-fall activities. The signal features of joint time-frequency representations are used for detection, while the support vector machine, which is based on the short-time Fourier transform feature, has been used in the classification process. An indoor experiment was conducted to emulate the elderly people's daily activities and the falling down event, where 50 trials were carried out by five adults for each of the activity. The detection results indicated that the forward scattering radar has a high ability in detecting the micro-Doppler signatures generated from the low speed motion of a human body segments during daily activities. The preliminary classification results are 100% for the corresponding free fall-sitting on a chair, free fall-sitting on the floor, and for all three activities

Micro-doppler detection in forward scattering radar: theoretical analysis and experiment

Forward scatter radar (FSR) is actively studied in the field of radars, as it has many advantages such as robust to radar absorbing material and possibility in target recognition. In many radar systems, micro-Doppler signature is one of the most distinguished information used for target recognition. Yet, there is lacking in established work on investigating the feasibility of using FSR to detect and analyse micro-Doppler signature generated from micro-motions of moving targets. Hence, a theoretical and experimental investigation of using the FSR to detect micro-Doppler signatures is presented. The preliminary results for both theoretical and experiment investigations verified that the FSR system is capable to detect the micro-Doppler signature for a swinging pendulum attached to the moving trolley

Improvement in Renal Function and Reduction in Serum Uric Acid with Intensive Statin Therapy in Older Patients: A Post Hoc Analysis of the SAGE Trial

BACKGROUND: Improvement in renal function and decreases in serum uric acid (SUA) have been reported following prolonged high-intensity statin (HMG-CoA reductase inhibitor) therapy. This post hoc analysis of the SAGE trial examined the effect of intensive versus less intensive statin therapy on renal function, safety, and laboratory parameters, including SUA, in elderly coronary artery disease (CAD) patients (65–85 years) with or without chronic kidney disease (CKD). METHODS: Patients were randomized to atorvastatin 80 mg/day or pravastatin 40 mg/day and treated for 12 months. Patients were stratified using Modification of Diet in Renal Disease (MDRD) estimated glomerular filtration rates (eGFRs) in CKD (eGFR <60 mL/min/1.73 m(2)) and non-CKD populations. RESULTS: Of the 893 patients randomized, 858 had complete renal data and 418 of 858 (49 %) had CKD (99 % Stage 3). Over 12 months, eGFR increased with atorvastatin and remained stable with pravastatin (+2.38 vs. +0.18 mL/min/1.73 m(2), respectively; p < 0.0001). MDRD eGFR improved significantly in both CKD treatment arms; however, the increased eGFR in patients without CKD was significantly greater with atorvastatin (+2.08 mL/min/1.73 m(2)) than with pravastatin (−1.04 mL/min/1.73 m(2)). Modest reductions in SUA were observed in both treatment arms, but a greater fall occurred with atorvastatin than with pravastatin (−0.52 vs. −0.09 mg/dL, p < 0.0001). Change in SUA correlated negatively with changes in eGFR and positively with changes in low-density lipoprotein cholesterol. Reports of myalgia were rare (3.6 % CKD; 5.7 % non-CKD), and there were no episodes of rhabdomyolysis. Elevated serum alanine and aspartate transaminase to >3 times the upper limit of normal occurred in 4.4 % of atorvastatin- and 0.2 % of pravastatin-treated patients. CONCLUSION: Intensive management of dyslipidemia in older patients with stable coronary heart disease may have beneficial effects on renal function and SUA