65 research outputs found
Systolic peak detection in acceleration photoplethysmograms measured from emergency responders in tropical conditions
Photoplethysmogram (PPG) monitoring is not only essential for critically ill patients in hospitals or at home, but also for those undergoing exercise testing. However, processing PPG signals measured after exercise is challenging, especially if the environment is hot and humid. In this paper, we propose a novel algorithm that can detect systolic peaks under challenging conditions, as in the case of emergency responders in tropical conditions. Accurate systolic-peak detection is an important first step for the analysis of heart rate variability. Algorithms based on local maxima-minima, first-derivative, and slope sum are evaluated, and a new algorithm is introduced to improve the detection rate. With 40 healthy subjects, the new algorithm demonstrates the highest overall detection accuracy (99.84% sensitivity, 99.89% positive predictivity). Existing algorithms, such as Billauer's, Li's and Zong's, have comparable although lower accuracy. However, the proposed algorithm presents an advantage for real-time applications by avoiding human intervention in threshold determination. For best performance, we show that a combination of two event-related moving averages with an offset threshold has an advantage in detecting systolic peaks, even in heat-stressed PPG signals.Mohamed Elgendi, Ian Norton, Matt Brearley, Derek Abbott, Dale Schuurman
Photoelectrochemical Properties of Thin Films of Cadmium, Zinc, and Magnesium Porphyrins with Pyridyl Group
Independent Determinants of Second Derivative of the Finger Photoplethysmogram among Various Cardiovascular Risk Factors in Middle-Aged Men
Controlled splenorenal shunt for esophageal varices with the long term clinical observations
Endoscope assisted terminal esophago-proximal gastrectomy for the treatment of esophageal varices in portal hypertension —Late results and an analysis of the mechanisms of recurrence—
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