Search results for "plethysmography"
showing 10 items of 84 documents
Clinical-anamnestic and instrumental data in outpatients suffering from venous disease
1995
The authors studied 200 consecutive outpatients with symptoms due to venous disease of the lower limbs. All the patients underwent anamnestic, clinical and instrumental evaluation (c.w. Doppler velocimetry and strain-gauge plethysmography). The results of this study showed that some anamnestic and clinical data are significantly related to venous disease detected by instrumental techniques. The superficial and deep vein hypertension were, instead, correlated to oral contraceptive use.
Ticlopidine in the Treatment of Multiple Atherosclerotic Arteriopathy: a Strain Gauge Plethysmography and Döppler Spectrum Analysis Evaluation
1987
The effect of ticlopidine was compared with flunarizine in patients with iliac–femoral and / or femoral–popliteal arteriosclerotic arteriopathy accompanied by lesions of the cervical arteries of no haemodynamic significance. In the lower limbs, plethysmography (strain gauge measurements) and Döppler ultrasonography integrated by spectral analysis of the cervical arteries showed qualitative and quantitative improvements of the regional haematic flow. Side-effects were negligible which suggests that ticlopidine is useful in the treatment of multiple arteriosclerotic arteriopathy.
Multispectral, Fluorescent and Photoplethysmographic Imaging for Remote Skin Assessment
2017
Optical tissue imaging has several advantages over the routine clinical imaging methods, including non-invasiveness (does not change the structure of tissues), remote operation (avoids infection) and ability to quantify the tissue condition by means of specific image parameters. Dermatologists and other skin experts need compact (preferably pocket-size), self-sustained and easy-to-use imaging devices. The operational principles and designs of ten portable in-vivo skin imaging prototypes developed at the Biophotonics Laboratory of Institute of Atomic Physics and Spectroscopy, University of Latvia during the recent five years are presented in this paper. Four groups of imaging devices are con…
PPG embedded system for blood pressure monitoring
2014
In this work, we have designed and implemented a microcontroller-based embedded system for blood pressure monitoring through a PhotoPlethysmoGraphic (PPG) technique. In our system, it is possible to perform PPG measurements via reflectance mode. Hardware novelty of our system consists in the adoption of Silicon PhotoMultiplier detectors. The signal received from the photodetector is used to calculate the instantaneous heart rate and therefore the heart rate variability. The obtained results show that, by using our system, it is possible to easily extract both the PPG and the breath signal. These signals can be used to monitor the patients during the convalescence both in hospital and at hom…
Cardiac sympathetic activation and parasympathetic withdrawal during psychosocial stress exposure in 6‐month‐old infants
2020
Infant autonomic reactivity to stress is a potential predictor of later life health complications, but research has not sufficiently examined sympathetic activity, controlled for effects of physical activity and respiration, or studied associations among autonomic adjustments, cardiac activity, and affect in infants. We studied 278 infants during the repeated Still-Face Paradigm, a standardized stressor, while monitoring cardiac activity (ECG) and respiratory pattern (respiratory inductance plethysmography). Video ratings of physical activity and affect were also performed. Respiratory sinus arrhythmia (RSA) and T-wave amplitude (TWA) served as noninvasive indicators of cardiac parasympathe…
Cardiovascular effects of impulse noise, road traffic noise, and intermittent pink noise at LAeq = 75 dB, as a function of sex, age, and level of anx…
1992
In a previous paper, in which the experimental conditions of the present research are fully described (Parrot et al., this issue), heart rate (HR) was studied in 60 male and in 60 female subjects in response to a pile-driver noise (P), a gunfire noise (G), a road traffic noise (T), and an intermittent pink noise (R), all noises being emitted at the same LAeq = 75 dB for 15 min. Digital pulse level (PL) responses were concomitantly surveyed by the use of pulse oximetry, allowing continuous arterial oxygen saturation (SaO2) readings. An index of pulse reactivity (PRI) could be calculated. Arterial blood pressure was measured 7 times from the beginning to the end of each trial. At rest, within…
The Effects of Prostaglandin E-1 in Patients with Intermittent Claudication
2006
Aim of the study is to evaluate the effects of Prostaglandin E-1 (PGE-1) in patients with peripheral arterial disease (PAD) at the 2nd b stage Fontaines classification. The study, controlled, single blinded, enrolled 123 patients with intermittent claudication that were randomised in two groups; the first group received a treatment with PGE-1 while the second one received a pentoxifylline-buflomedil association by venous infusion. We evaluated: Pain Free Walking Distance (PFWD), Maximum Walking Distance (MWD), Rest Flow (RF), Peak Flow (PF), Basal (BVR) and Minimal Vascular Resistance (MVR) with a strain gauge plethysmograph, Resting Flow (RF), Peak Flow (PF), time to reach the Peak Flow (t…
A silicon photomultiplier-based analog front-end for DC component rejection and pulse wave recording in photoplethysmographic applications
2022
The growing attention towards healthcare and the constant technological innovations in the field of semiconductor components have allowed a widespread availability of smaller devices, suitable to be worn and able to continuously acquire physiological signals. Wearable devices are, however, more prone to yield signals corrupted by artifacts caused by movement. This issue is particularly relevant in photoplethysmographic (PPG) applications where also, to exploit the whole dynamic range of the acquisition device, the DC component of the signal should be removed and the AC component amplified. In this context, we have designed and realized an analog front-end (AFE) suitable to be integrated wit…
Reliability of Short-Term Heart Rate Variability Indexes Assessed through Photoplethysmography
2018
The gold standard method to monitor heart rate variability (HRV) comprises measuring the time series of interbeat interval durations from electrocardiographic (ECG) recordings. However, due to the widespread use, simplicity and usability of photoplethysmographic (PPG) techniques, monitoring pulse rate variability (PRV) from pulse wave recordings has become a viable alternative to standard HRV analysis. The present study investigates the accuracy of PRV, measured as a surrogate of HRV, for the quantification of descriptive indexes computed in the time domain (mean, variance), frequency domain (low-to-high frequency power ratio LF/HF, HF band central frequency) and information domain (entropy…
Two-stage multi-Gaussian fitting of conduit artery photoplethysmography waveform during induced unilateral hemodynamic events.
2014
Photoplethysmography (PPG) is an optical technique with high diagnostic potential, yet clinical applications remain underdeveloped. Standardization of signal recording and quantification of waveform are essential prerequisites for broader clinical use. The aim of this study was to utilize a two-stage multi-Gaussian fitting technique in order to examine the parameters of conduit artery PPG waveform recorded during increasing the unilateral regional vascular resistance (RVR). This study was conducted on 14 young and healthy volunteers; various external compressions (ECs) were performed by inflating a tight cuff at 0, 40, 80, and 200 mmHg, while registering femoral PPG (wavelength 880 nm), dia…