Fish behavior and its use in the capture and culture of fishes

Fishery management, Behaviour, Food fish, Fish culture, Conferences

A Pulsatile Optical Tissue Phantom for the Investigation of Light-Tissue Interaction in Reflectance Photoplethysmography

The aim of this study was to investigate the effect of emitter-detector separation distance and arterial depth in reflectance photoplethysmography (PPG), utilizing a homogenous pulsatile phantom that exhibits the broad optical absorbance and scattering properties of human tissue. The developed phantom comprised of embedded silicone arteries (outer diameter = 4 mm) that were arranged parallel to one another at nine increasing depths (3.2 mm to 24.4 mm). A pulsatile pump (Harvard Apparatus, MA, USA) circulated a blood imitating fluid through the vessels at the desired heart rate (60 bpm) and stroke volume (5 Lmin-1). The PPG sensor’s emitter and detector were isolated on a translation bridge to provide a computer-controlled separation distance between them. Recordings were taken at each vessel depth for emitter-detector separation distances from 2 mm to 8 mm in 0.1 mm steps. The optimum separation distance between the emitter and detector for vessels between depths of 3.2 mm and 10.5 mm was between 3.7 and 4.3 mm, suggesting that the maximum penetration of IR (930 nm) light in a homogenous pulsatile phantom is no greater than 10.5 mm

Fabricating Novel PDMS Vessels for Phantoms in Photoplethysmography Investigations

This paper introduces a novel technique for the development of custom polydimethylsiloxane (PDMS) vessels for use in phantom technologies. The method involves continuous dip coating of commercial silicone tubes with rapid curation in a single controlled process. The technique accommodates the production of different vessel diameters, wall thicknesses (56 μm-80 μm) and mechanical properties. Clear phantoms were fabricated to compare the commercial silicone tubes against the customs vessels. A pulsatile fluidic pump (BDCLabs, CO, USA) driven by a computer controlled linear motor generated the pulsatile flow through the phantom. The resulting flow profile, using the custom vessels, simulates human blood flow and the detected contact PPG signal from the phantom closely resembles the morphology of in vivo PPG waveforms with signal-to-noise ratios of 38.16 dB and 40.59 dB, compared to the closest commercially-available tubing at 5.38 dB and 10.59 dB for the red and infrared wavelengths respectively. The rigidity and thick walls of commercial silicone tubes impede the expansion of the tubing under systolic pressure. This technique eliminates this common limitation in phantom development

Pilot investigation of anterior fontanelle photoplethysmographic signals and their suitability in estimating arterial oxygen saturation

There is a need for more reliable, non-invasive and alternative measurement sites for the monitoring of arterial blood oxygen saturation in critically ill newborns at times of peripheral compromise. A pilot investigation on 14 Intensive Care Unit (ICU) newborns was conducted utilizing custom-made reflectance photoplethysmographic (PPG) sensors placed at the fontanelle and foot. The results suggest that the fontanelle is sensitive to changes in saturation, where saturation values obtained from the custom sensor were compared against commercial pulse oximeter values and results from a blood gas analyzer, however careful placement of the sensor at the fontanelle is an issue that needs further investigation

Esophageal SpO2 measurements from a pediatric burns-patient: A case study

Pulse oximetry is being used in everyday clinical practice in anesthesia utilizing peripheral saturation sensors. However, it may be unreliable in certain clinical situations such as peripheral hypoperfusion. Similar situations occur in burns patients and more importantly burns to extremities which limit the sites available for measurement of peripheral oxygen saturation (SpO2). To overcome these limitations, the esophagus has been investigated as an alternative measurement site, as perfusion may be preferentially preserved centrally. A miniaturized reflectance esophageal saturation (SpO2 probe has been constructed utilizing infrared and red photodiodes and a photodetector. Our case study was aimed at evaluating the reliability of esophageal pulse oximetry in a major burns infant. Measurable photoplethysmographic (PPG) traces and SpO2 values were obtained in the neonatal esophagus. It was found that the esophageal pulse oximeter results were in good agreement with oxygen saturation measurements obtained by a commercial ear lobe pulse oximeter. This study suggests that the esophagus can be used as an alternative site for monitoring arterial blood oxygen saturation by pulse oximetry in burned infants

Development of an Optoelectronic Sensor for the Investigation of Photoplethysmographic Signals from the Anterior Fontanel of the Newborn

There is a need for more reliable, non-invasive and alternative measurement sites for the monitoring of arterial blood oxygen saturation in critically ill newborns at times of peripheral compromise. The interior fontanelle, a unique anatomical feature of the newborn, has been presented as an alternative site for the estimation of oxygen saturation. A multi-wavelength non-invasive optoelectronic sensor has been designed and developed or the investigation of photoplethysmographic (PPG) signals and blood oxygen saturation values from the fontanelle. In vivo thermal tests of the optical sensor show that under normal operating conditions the heating at the skin surface was negligible(<0.1°C). Good quality PPGs with large amplitudes and high signal to noise ratio were recorded at all three (red, infrared and green) wavelengths prior to clinical measurements

Design and development of a novel multi-channel photoplethysmographic research system

Photoplethysmography (PPG) is a technique that uses light to non-invasively obtain a volumetric measurement of an organ with each cardiac cycle. Pulse Oximetry (PO) is an empirical technique which allows the arterial blood oxygen saturation (SpO2) evaluation from the PPG signals. There have been many reports in the literature suggesting that other arterial blood chemical components can be evaluated from the PPG signals. Most attempts to perform such evaluation on empirical bases have failed, especially for components concentrations. This paper introduces a non-empirical rational theory called Dynamic Pulsatile Spectroscopy (DPS) which can be used to analytically investigate the phenomena of PPG. The DPS theory provides the mathematically rigid method of how PPG signals can be used for arterial blood analysis to evaluate its chemical component concentrations and molar fractions spectroscopically and transcutaneously. It also highlights what other signals might be required for such evaluation. DPS opens the possibility of extending PPG application for blood analysis beyond conventional PO. The DPS basic principles are introduced in this paper

The Sensing Endotracheal Tube

Current pulse oximetry sensors are not very wellsuited to use in anaesthetised patients as it has been shownthat during episodes of reduced peripheral circulation they donot function correctly or fail all together [1], [2]. To addressthis problem a new design for a photoplethysmography (PPG)endotracheal (ET) sensor to monitor pulse rate and oxygensaturation (SpO2) internally is presented. Flexible printedcircuit board (PCB) technology and miniature optoelectroniccomponents have been implemented and integrated with acustom instrumentation system [3]. The sensor adheres andconforms to the curvature of standard french-gauge 7 and 8ET tubes at the point just above the inflatable cuff within thelaryngeal positioning markings. A 3D-modelled, optically clear,soft silicon encapsulation electronically and thermally isolatesthe electronic components whilst providing a smooth surface toaid the insertion on the ET tube during standard intubationprocedures. A pilot study with 5 patients (3 Female, 2 Male),undergoing abdominal and limb laproscopic procedures hasdemonstrated the operation of the sensing ET tube, showinggood quality red and infra-red PPG signals. Preliminary signalanalysis reveals heart rate can be measured via PPG success-fully, with saturation (SpO2) readings in close agreement withthe commercial monitors of 97.9% (STD 0.2%) and 98.6% (STD 0.8%) respectivel

Photoplethysmographic and SpO2 readings from the neonatal anterior fontanelle: a case study

There is a need for a more reliable, noninvasive and alternative measurement site for the monitoring of arterial blood oxygen saturation in critically ill neonates when peripheral perfusion is poor. The anterior fontanelle, a unique anatomical feature of the neonate, has been presented as an alternative site for the estimation of arterial blood oxygen saturation (SpO2). A new fontanelle photoplethysmographic sensor and processing system has been developed to investigate fontanelle photoplethysmographic (PPG) signals and estimate SpO2 values at this anatomical location. Preliminary clinical trials have shown that good quality PPG signals with large amplitudes and high signal to noise ratio can be obtained from the neonatal fontanelle. The estimation of SpO2 values from the fontanelle were in broad agreement with a commercial foot pulse oximeter

Optical analysis of Lithium Carbonate: Towards the development of a Portable Lithium Blood Level analyzer for Bipolar Disorder Patients

Lithium medication is the gold standard of treatment in Bipolar Disorder patients, preventing and reducing mood swings and suicidality. However, despite its effectiveness, it is a potentially hazardous drug requiring regular monitoring of blood levels to ensure toxic levels are not reached. This paper describes the first steps towards developing a new portable device that can be used by Bipolar Disorder patients to facilitate the analysis of lithium blood levels at home. Solutions of lithium carbonate have been optically fingerprinted using a high-end spectrophotometer. Preliminary measurements indicate that while the visible to near infrared region of the absorption spectra fall heavily within the water band, measurements in the Ultraviolet region show a strong distinction between different lithium concentrations. The optical spectra of Lithium in the 220 nm to 230 nm region demonstrated the ability to differentiate between concentrations representing those found in patients