Optical assessment of recovery of tissue blood supply after removal of externally applied pressure

Murray, Alan; Marjanovic, D

doi:10.1007/bf02534102

Cited by 18 publications

(7 citation statements)

References 9 publications

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“…This is consistent with previous studies comparing PPG and LD. Even if the two measures were not equivalent, a good correlation was found between LD and PPG in different conditions such as inspiratory-induced vasoconstrictive episodes [32] or wound healing [33], but its use and reliability in critical conditions was not tested. Some studies have concluded that finger PPG signal was inappropriate due to the poor signal obtained [34] while others stated that this method could have an interest.…”

Section: Discussionmentioning

confidence: 99%

A new device for continuous assessment of gut perfusion: proof of concept on a porcine model of septic shock

et al. 2014

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IntroductionWe evaluate an innovative device consisting of an enteral feeding tube equipped with a photoplethysmography (PPG) sensor in contact with the duodenal mucosa. This study aims to determine if the PPG signal, composed of a continuous (PDC) and a pulsatile part (PAC), is a reliable method to assess gut perfusion in a porcine model of septic shock.MethodFourteen piglets were anesthetized and mechanically ventilated. They were randomly assigned to two groups: the nonseptic (NS) group received an infusion of Ringer’s lactate solution (RL) alone, the septic (S) group received in addition a suspension of live Pseudomonas aeruginosa. Heart rate (HR), pulse oximetry (SpO2), mean arterial pressure (MAP), cardiac index (CI) and serum lactates were recorded and gut microcirculation (GM) was monitored with a laser Doppler probe applied on the duodenal serosa. PDC and PAC were given by the PPG probe inserted in the duodenum. Data was collected every 15 minutes (t0, t15…) during 150 minutes (t150). After administration of the bacteria suspension (t0), resuscitation maneuvers were performed following a defined algorithm. GM PAC, and PDC were expressed as variation from baseline (GMvar, PACvar, PDCvar). Analysis of variance (ANOVA) with repeated measures was performed to compare hemodynamic variables, with Bonferroni correction as post hoc analysis on t0, t60 and t150.ResultsOne piglet was withdrawn from analysis due to a defective probe. S group (six piglets) received resuscitation therapy while NS group (seven piglets) did not. A significant group effect was found for the all parameters except HR. Post hoc analysis found a significant decrease for GM and PAC at t60. The correlation between PAC, PDC and microcirculatory parameters were as follows: rPACvar-GMvar = 0.496, P <0.001, rPDCvar-GMvar = 0.244; P = 0.002. In the septic group, correlations were as follows: rPAC-lactate = -0.772, P <0.001; rPDC-lactate = -0.681, P <0.01). At the onset of shock, a decrease of PAC, PDC and GM occurred before the alteration of MAP.ConclusionsPAC and PDC decreased at the onset of shock and were correlated with GM and lactate. These results confirm that PPG signal reliably reflects the early perfusion alteration of the gut. Further studies should assess the clinical use of this device.

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Section: Discussionmentioning

confidence: 99%

A new device for continuous assessment of gut perfusion: proof of concept on a porcine model of septic shock

et al. 2014

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“…The results of this set of measurements are shown in figure 16, which represents the averaged signal intensity obtained for each cuff pressure level. It was expected that the increasing pressure applied by the cuff would reduce the capillary blood flow (Murray and Marjanovic 1997) and result in an increase of the total amount of blood in the skin and underlying tissue (Douven and Lucassen 2000). Measurements at different pressures show no noticeable dependence of the reflectance signal on the capillary blood flow/perfusion change in volume fraction in this tissue compartment.…”

Section: 'Distance Measurement' Measurementsmentioning

confidence: 99%

The electromagnetic response of human skin in the millimetre and submillimetre wave range

et al. 2009

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Recent studies of the minute morphology of the skin by optical coherence tomography revealed that the sweat ducts in human skin are helically shaped tubes, filled with a conductive aqueous solution. This, together with the fact that the dielectric permittivity of the dermis is higher than that of the epidermis, brings forward the supposition that as electromagnetic entities, the sweat ducts could be regarded as low Q helical antennas. The implications of this statement were further investigated by electromagnetic simulation and experiment of the in vivo reflectivity of the skin of subjects under varying physiological conditions (Feldman et al 2008 Phys. Rev. Lett. 100 128102). The simulation and experimental results are in a good agreement and both demonstrate that sweat ducts in the skin could indeed behave as low Q antennas. Thus, the skin spectral response in the sub-Terahertz region is governed by the level of activity of the perspiration system and shows the minimum of reflectivity at some frequencies in the frequency band of 75-110 GHz. It is also correlated to physiological stress as manifested by the pulse rate and the systolic blood pressure. As such, it has the potential to become the underlying principle for remote sensing of the physiological parameters and the mental state of the examined subject.

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“…It has been shown that the mattress characteristics and the skin-support surface interface affect the accuracy of the interface pressure measurement (ALLEN et aL, 1993a;REDDY et aL, 1984 BADER, 1990;BADER and CANT, 1988;BALDWIN, 2000;FELDMAN et al, 1993;GOOSSENS et aL, 1994;LIU et al, 1999;NEWSON et al, 1981;SACHSE et al, 1998;SANADA et al, 1995;XAKELLIS et al, 1991EK et aL, 1987FELDMAN et al, 1993;FRANTZ and XAKELLIS, 1989;FRANTZ et al, 1993;HERRMAN et al, 1999;JACOBS, 1989;MAYROVITZ and SIMS, 2002;MAYROVITZ et al, 2003;MAYROVITZ et al, 1997;MEINDERS et aL, 1996;PATEL et al, 1999;SACHSE et al, 1998;SANTOS et al, 2003;SCHUBERT, 1991;SCHUBERT and FAGRELL, 1989;SCHUBERT and H~RAUD, 1994;SCHUBERT et al, 1995;XAKELLIS et al, 1991;MAYROVlTZ et aL, 1999MAYROVITZ and SMITH, 1998;MAYROVITZ et al, 1997;THORFINN et al, 2002BENNETT et aL, 1979LEE et al, 1979;MURRAY and MARJANOVIC, 1997NIITSUMA et al, 2003BOLUND and HOLSTEIN, 1976DINSDALE,...…”

Section: Interface Pressure and Shear Forcesmentioning

confidence: 96%

Evaluation of antidecubitus mattresses

Jönsson

Lindén

Lindgren

et al. 2005

Med. Biol. Eng. Comput.

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Pressure sores are a current problem in hospitals and care of the elderly, leading to protracted hospital stays and a high care burden. The trauma for the patients is severe, and the cost of pressure sore prevention and treatment, is considerable. Antidecubitus mattresses are used for prevention and in treatment, but they also contribute to the cost of treating pressure sores. The problem highlighted in the review is that the mattresses' effectiveness in preventing and treating pressure sores has not been sufficiently evaluated. When antidecubitus mattresses are evaluated, it is often only with regard to aspects of the interface pressure and the mattresses' ability to redistribute the pressure. The review points out the important observation that, to be able to evaluate the efficacy of the antidecubitus mattress, the mattress's effect on tissue viability needs to be studied. The parameters that ought to be considered when evaluating a support surface are: interface pressure, pressure and blood flow distribution, temperature and humidity in the skin-support surface interface. The authors propose that the effect on tissue viability of external loading can be assessed by simultaneous measurement of the interface pressure and tissue perfusion.

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Optical assessment of recovery of tissue blood supply after removal of externally applied pressure

Cited by 18 publications

References 9 publications

A new device for continuous assessment of gut perfusion: proof of concept on a porcine model of septic shock

A new device for continuous assessment of gut perfusion: proof of concept on a porcine model of septic shock

The electromagnetic response of human skin in the millimetre and submillimetre wave range

Evaluation of antidecubitus mattresses

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