Pub Date : 2002-12-01DOI: 10.1109/IEMBS.2002.1053267
A. Kholodnykh, I. Petrova, M. Motamedi, R. Esenaliev
Accurate measurements of tissue optical properties are needed for many diagnostic and therapeutic applications of optical techniques. OCT recently proposed for high-resolution imaging in tissue can potentially be applied for accurate and noninvasive measurement of tissue optical properties. We proposed a bifocal technique for accurate measurement of tissue total attenuation coefficient with OCT. This technique utilizes detection of OCT signals from two focal planes within scattering media that allows correction for confocal function. In this paper, we studied the capability of the bifocal technique to measure accurately total attenuation coefficient in scattering media simulating tissue with high and low scattering. The experiments were performed with tissue phantoms: suspension of polystyrene microspheres in water with different total attenuation coefficients. Our studies demonstrated that the bifocal technique substantially improves accuracy of measurement: absolute values of total attenuation coefficient can be measured with 7% accuracy (compared with theoretically calculated values), while the accuracy of relative measurements can be 1.5%. Our results indicate that the bifocal technique is a promising approach to accurate measurement of total attenuation coefficient in tissues.
{"title":"Bifocal technique for accurate measurement of total attenuation coefficient in scattering media with OCT","authors":"A. Kholodnykh, I. Petrova, M. Motamedi, R. Esenaliev","doi":"10.1109/IEMBS.2002.1053267","DOIUrl":"https://doi.org/10.1109/IEMBS.2002.1053267","url":null,"abstract":"Accurate measurements of tissue optical properties are needed for many diagnostic and therapeutic applications of optical techniques. OCT recently proposed for high-resolution imaging in tissue can potentially be applied for accurate and noninvasive measurement of tissue optical properties. We proposed a bifocal technique for accurate measurement of tissue total attenuation coefficient with OCT. This technique utilizes detection of OCT signals from two focal planes within scattering media that allows correction for confocal function. In this paper, we studied the capability of the bifocal technique to measure accurately total attenuation coefficient in scattering media simulating tissue with high and low scattering. The experiments were performed with tissue phantoms: suspension of polystyrene microspheres in water with different total attenuation coefficients. Our studies demonstrated that the bifocal technique substantially improves accuracy of measurement: absolute values of total attenuation coefficient can be measured with 7% accuracy (compared with theoretically calculated values), while the accuracy of relative measurements can be 1.5%. Our results indicate that the bifocal technique is a promising approach to accurate measurement of total attenuation coefficient in tissues.","PeriodicalId":60385,"journal":{"name":"中国地球物理学会年刊","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73480268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-01DOI: 10.1109/IEMBS.2002.1134468
S. Cranstoun, G. Worrell, J. Echauz, B. Litt
Criticality is a property of complex dynamical systems that can produce large energy release. Examples in nature of such systems are earthquakes, avalanches and volcanoes. It has been recently demonstrated that networks of integrate-and-fire neurons also exhibit such critical behavior where the system energy is related to the degree of synchronized neuronal firing. We have examined electrographic recordings from human epileptic hippocampus and demonstrate that this tissue exhibits self-organized criticality. These findings may explain energy bursting recently found to occur prior to epileptic seizures in the hippocampus and may connect them to integrate-and-fire models.
{"title":"Self-organized criticality in the epileptic brain","authors":"S. Cranstoun, G. Worrell, J. Echauz, B. Litt","doi":"10.1109/IEMBS.2002.1134468","DOIUrl":"https://doi.org/10.1109/IEMBS.2002.1134468","url":null,"abstract":"Criticality is a property of complex dynamical systems that can produce large energy release. Examples in nature of such systems are earthquakes, avalanches and volcanoes. It has been recently demonstrated that networks of integrate-and-fire neurons also exhibit such critical behavior where the system energy is related to the degree of synchronized neuronal firing. We have examined electrographic recordings from human epileptic hippocampus and demonstrate that this tissue exhibits self-organized criticality. These findings may explain energy bursting recently found to occur prior to epileptic seizures in the hippocampus and may connect them to integrate-and-fire models.","PeriodicalId":60385,"journal":{"name":"中国地球物理学会年刊","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89110082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-01DOI: 10.1109/IEMBS.2002.1053370
Li-Qun Zhang, S.G. Chung, E.M. van Rey, A.F. Lin, Z. Bai, T. Grant, E. Roth
Spastic hypertonia has reflex/non-reflex and dynamic/static components, which were investigated in ankles of 24 spastic hemiparetic and 32 normal subjects. Furthermore, the spastic ankles were treated with an intelligent stretching device with outcome evaluated in terms of phasic and tonic stretch-reflex gains, reflex threshold, joint elastic stiffness, and viscous damping. We found that joint elastic stiffness was increased in spastic ankles, especially in the plantar flexors. The increase was due to an increase in passive stiffness instead of intrinsic stiffness. Viscous damping was increased in spastic plantar flexors. Reflexively, spastic ankles showed higher dynamic reflex gain in spastic plantar flexors, indicating exaggerated phasic stretch reflex. The static stretch-reflex gain was increased in spastic ankles, indicating hyperactive tonic stretch reflex, and spastic muscles did not regulate tonic stretch reflex as controls did. Reflex hyperexcitability in spasticity was associated with both increased tendon reflex gain and decreased threshold. After stretching, the patients were able to generate higher plantar flexion MVC torque, which was corroborated by increased torques induced by matched electrical stimulation of the spastic muscles. They were also able to move in large ROM. Achilles tendon properties evaluated by ultrasonography corroborated the strength increase.
{"title":"Evaluation and treatment of spastic hypertonia and contracture","authors":"Li-Qun Zhang, S.G. Chung, E.M. van Rey, A.F. Lin, Z. Bai, T. Grant, E. Roth","doi":"10.1109/IEMBS.2002.1053370","DOIUrl":"https://doi.org/10.1109/IEMBS.2002.1053370","url":null,"abstract":"Spastic hypertonia has reflex/non-reflex and dynamic/static components, which were investigated in ankles of 24 spastic hemiparetic and 32 normal subjects. Furthermore, the spastic ankles were treated with an intelligent stretching device with outcome evaluated in terms of phasic and tonic stretch-reflex gains, reflex threshold, joint elastic stiffness, and viscous damping. We found that joint elastic stiffness was increased in spastic ankles, especially in the plantar flexors. The increase was due to an increase in passive stiffness instead of intrinsic stiffness. Viscous damping was increased in spastic plantar flexors. Reflexively, spastic ankles showed higher dynamic reflex gain in spastic plantar flexors, indicating exaggerated phasic stretch reflex. The static stretch-reflex gain was increased in spastic ankles, indicating hyperactive tonic stretch reflex, and spastic muscles did not regulate tonic stretch reflex as controls did. Reflex hyperexcitability in spasticity was associated with both increased tendon reflex gain and decreased threshold. After stretching, the patients were able to generate higher plantar flexion MVC torque, which was corroborated by increased torques induced by matched electrical stimulation of the spastic muscles. They were also able to move in large ROM. Achilles tendon properties evaluated by ultrasonography corroborated the strength increase.","PeriodicalId":60385,"journal":{"name":"中国地球物理学会年刊","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90981402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-01DOI: 10.1109/IEMBS.2002.1136849
A. Spector, W. Brownell, A. Popel
We have found that the band pass characteristics of the cochlear outer hair cell can be improved by introducing the piezoelectric properties of the cell membrane. In contrast to the conventional analysis, the cell membrane receptor potential does not tend to zero and at any frequency is greater than a limiting value. The piezoelectric properties cause an additional, strain-dependent, displacement current in the cell wall. In short cells, we have found that for the low-frequency value about 2-3 mV and the strain level 0.1% the receptor potential can reach 0.4 mV throughout the whole frequency range. In long cells, we have found that the effect of the piezoelectric properties is negligible.
{"title":"Effect of outer hair cell membrane piezoelectric properties on the receptor potential under high-frequency conditions","authors":"A. Spector, W. Brownell, A. Popel","doi":"10.1109/IEMBS.2002.1136849","DOIUrl":"https://doi.org/10.1109/IEMBS.2002.1136849","url":null,"abstract":"We have found that the band pass characteristics of the cochlear outer hair cell can be improved by introducing the piezoelectric properties of the cell membrane. In contrast to the conventional analysis, the cell membrane receptor potential does not tend to zero and at any frequency is greater than a limiting value. The piezoelectric properties cause an additional, strain-dependent, displacement current in the cell wall. In short cells, we have found that for the low-frequency value about 2-3 mV and the strain level 0.1% the receptor potential can reach 0.4 mV throughout the whole frequency range. In long cells, we have found that the effect of the piezoelectric properties is negligible.","PeriodicalId":60385,"journal":{"name":"中国地球物理学会年刊","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89680899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-01DOI: 10.1109/IEMBS.2002.1137060
R. Sharma, J. Kohn, P. Moghe
This study examined the modulation of cell migratory responsiveness to protein-adsorbed poly(ethylene glycol) (PEG) variant copolymers. To this end, fibronectin was adsorbed to equivalent levels on copolymers based on a family of tyrosine/PEG derived polycarbonates. Atomic force microscopy (AFM) revealed unique protein distributions for each copolymer system, indicating that although equal amounts of ligand are presented, the concentration of PEG in the underlying substrate can effect the adsorbed ligand. Consequently, quantitation of fibronectin RGD-binding sites on the protein-adsorbed copolymers revealed that cell-binding sites were maximized at intermediate concentrations of PEG. Our migration studies demonstrated that increasing PEG in the copolymer increased cell speed monotonically up to an intermediate PEG level where a maximum speed was reached. After incubating cells on ligand adsorbed copolymers, higher PEG levels elicited equivalent number of cell-binding sites relative to those on intermediate levels of PEG. Integrin inhibition studies showed that /spl alpha//sub 5//spl beta//sub 1/ was critical in modulating the number of RGD sites. Our AFM data suggests that rearrangement at higher PEG levels was facilitated by electrostatic repulsion, effecting fibronectin slippage at the polymer surface as well as conformational rearrangement revealing addition al RGD binding sites. Overall, we report on the finding that cell migratory responsiveness to a given ligand concentration can be further manipulated via systematic ligand changes due to the substrate PEG composition.
{"title":"Engineering cell motility via substrate incorporation of poly(ethylene glycol)","authors":"R. Sharma, J. Kohn, P. Moghe","doi":"10.1109/IEMBS.2002.1137060","DOIUrl":"https://doi.org/10.1109/IEMBS.2002.1137060","url":null,"abstract":"This study examined the modulation of cell migratory responsiveness to protein-adsorbed poly(ethylene glycol) (PEG) variant copolymers. To this end, fibronectin was adsorbed to equivalent levels on copolymers based on a family of tyrosine/PEG derived polycarbonates. Atomic force microscopy (AFM) revealed unique protein distributions for each copolymer system, indicating that although equal amounts of ligand are presented, the concentration of PEG in the underlying substrate can effect the adsorbed ligand. Consequently, quantitation of fibronectin RGD-binding sites on the protein-adsorbed copolymers revealed that cell-binding sites were maximized at intermediate concentrations of PEG. Our migration studies demonstrated that increasing PEG in the copolymer increased cell speed monotonically up to an intermediate PEG level where a maximum speed was reached. After incubating cells on ligand adsorbed copolymers, higher PEG levels elicited equivalent number of cell-binding sites relative to those on intermediate levels of PEG. Integrin inhibition studies showed that /spl alpha//sub 5//spl beta//sub 1/ was critical in modulating the number of RGD sites. Our AFM data suggests that rearrangement at higher PEG levels was facilitated by electrostatic repulsion, effecting fibronectin slippage at the polymer surface as well as conformational rearrangement revealing addition al RGD binding sites. Overall, we report on the finding that cell migratory responsiveness to a given ligand concentration can be further manipulated via systematic ligand changes due to the substrate PEG composition.","PeriodicalId":60385,"journal":{"name":"中国地球物理学会年刊","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88246215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-01DOI: 10.1109/IEMBS.2002.1137093
E. Alsberg, H. Kong, M.K. Smith, D.J. Mooneyl
Biodegradability is a critical polymer scaffold characteristic for tissue engineering applications. A scaffold for cell transplantation should provide mechanical support and structure in concert with the needs of newly developing tissue. Alginate hydrogels modified with specific adhesion ligands have previously been used to successfully engineer bone and cartilage tissue in vivo, but show negligible degradation in vitro and in viva. Gamma irradiating the alginate, which decreased the average molecular weight of the polymer chains, increased the rate of hydrogel degradation in viva and fibrous tissue ingrowth. Primary rat calvarial osteoblasts combined with gamma irradiated alginate modified with specific adhesion ligands significantly improved the rate, quality, and quantity of new bone tissue formed in vivo compared to the non-irradiated control condition. Control of both the degradation and adhesion characteristics of a polymer scaffold will be a powerful tool in regulating tissue regeneration processes.
{"title":"Controlled degradation of peptide modified hydrogels improves rate, quality, and quantity of in vivo bone formation","authors":"E. Alsberg, H. Kong, M.K. Smith, D.J. Mooneyl","doi":"10.1109/IEMBS.2002.1137093","DOIUrl":"https://doi.org/10.1109/IEMBS.2002.1137093","url":null,"abstract":"Biodegradability is a critical polymer scaffold characteristic for tissue engineering applications. A scaffold for cell transplantation should provide mechanical support and structure in concert with the needs of newly developing tissue. Alginate hydrogels modified with specific adhesion ligands have previously been used to successfully engineer bone and cartilage tissue in vivo, but show negligible degradation in vitro and in viva. Gamma irradiating the alginate, which decreased the average molecular weight of the polymer chains, increased the rate of hydrogel degradation in viva and fibrous tissue ingrowth. Primary rat calvarial osteoblasts combined with gamma irradiated alginate modified with specific adhesion ligands significantly improved the rate, quality, and quantity of new bone tissue formed in vivo compared to the non-irradiated control condition. Control of both the degradation and adhesion characteristics of a polymer scaffold will be a powerful tool in regulating tissue regeneration processes.","PeriodicalId":60385,"journal":{"name":"中国地球物理学会年刊","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82509537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-01DOI: 10.1109/IEMBS.2002.1053031
C. R. Patel, S. Poggi, C. Spong, R. Allen
We report on a tactile force-sensing glove worn by an obstetrician to measure the force applied on a fetal head during childbirth. The glove consists of five piezoresistive sensors strategically placed to measure normal forces applied to the head. The normal forces are converted to traction forces via laboratory calibrations. The sensors interface with a computer for real-time data acquisition and processing. The glove is being used to quantify and investigate clinician-applied forces during vaginal deliveries, with special focus on an obstetric emergency known as shoulder dystocia. A prototype version has been developed and tested with multiple birthing simulations, as well as six normal deliveries and one delivery with a compound presentation. We conclude that a tactile sensing glove can be used to study hand-applied forces during childbirth to better understand the relationship between different birthing procedures and the forces applied during them.
{"title":"Measuring hand-applied forces during childbirth","authors":"C. R. Patel, S. Poggi, C. Spong, R. Allen","doi":"10.1109/IEMBS.2002.1053031","DOIUrl":"https://doi.org/10.1109/IEMBS.2002.1053031","url":null,"abstract":"We report on a tactile force-sensing glove worn by an obstetrician to measure the force applied on a fetal head during childbirth. The glove consists of five piezoresistive sensors strategically placed to measure normal forces applied to the head. The normal forces are converted to traction forces via laboratory calibrations. The sensors interface with a computer for real-time data acquisition and processing. The glove is being used to quantify and investigate clinician-applied forces during vaginal deliveries, with special focus on an obstetric emergency known as shoulder dystocia. A prototype version has been developed and tested with multiple birthing simulations, as well as six normal deliveries and one delivery with a compound presentation. We conclude that a tactile sensing glove can be used to study hand-applied forces during childbirth to better understand the relationship between different birthing procedures and the forces applied during them.","PeriodicalId":60385,"journal":{"name":"中国地球物理学会年刊","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84326733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-01DOI: 10.1109/IEMBS.2002.1106610
K.K. Kondabatni, F. Hua, T. Cui, Y. Lvov, M. Mcshane
The miniaturization of biosensors has resulted in the need to develop new techniques to pattern various sensor elements with high resolution and fast response time. This paper describes the selective deposition of various sensor elements on glass as well as on silicon substrate by combining layer-by-layer electrostatic self-assembly, photolithography and avidin-biotin chemistry. Two methods have been developed for this selective patterning. The first method includes selective UV radiation of a coated photobiotin on glass substrate and covalent bonding of avidin-layered fluorescent nanoparticles to the irradiated areas. The second method involves lithography and self-assembly in a modified lift-off process. In both cases, the epifluorescence microscope images show high spatial resolution of patterned areas and excellent surface coverage. These patterns will be further developed for monitoring cell growth in tissue scaffolds.
{"title":"Micro-patterning of nanosensor elements using layer-by-layer self-assembly, avidin-biotin chemistry, and photolithography","authors":"K.K. Kondabatni, F. Hua, T. Cui, Y. Lvov, M. Mcshane","doi":"10.1109/IEMBS.2002.1106610","DOIUrl":"https://doi.org/10.1109/IEMBS.2002.1106610","url":null,"abstract":"The miniaturization of biosensors has resulted in the need to develop new techniques to pattern various sensor elements with high resolution and fast response time. This paper describes the selective deposition of various sensor elements on glass as well as on silicon substrate by combining layer-by-layer electrostatic self-assembly, photolithography and avidin-biotin chemistry. Two methods have been developed for this selective patterning. The first method includes selective UV radiation of a coated photobiotin on glass substrate and covalent bonding of avidin-layered fluorescent nanoparticles to the irradiated areas. The second method involves lithography and self-assembly in a modified lift-off process. In both cases, the epifluorescence microscope images show high spatial resolution of patterned areas and excellent surface coverage. These patterns will be further developed for monitoring cell growth in tissue scaffolds.","PeriodicalId":60385,"journal":{"name":"中国地球物理学会年刊","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89294628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-01DOI: 10.1109/IEMBS.2002.1053286
H. Brecht, Y. Petrov, D. Prough, D. Deyo, O. Hartrumpf, R. Esenaliev
During surgery associated with rapid blood loss, rapid fluid administration and transfusion of packed red blood cells, measurement of total hemoglobin concentration provides necessary information to direct decisions regarding transfusion. However, measurement of total hemoglobin concentration currently requires collection of a blood sample and either transport to a laboratory or centrifugation at the bedside. Recently we proposed to use optoacoustic technique for noninvasive and continuous monitoring of total hemoglobin concentration. High resolution of the optoacoustic technique may provide accurate measurement of total hemoglobin concentration by detecting and analyzing optoacoustic signals induced by short optical pulses in blood circulating in arteries or veins. We designed, built, and tested in vitro and in preliminary in vivo experiments a portable optoacoustic system for monitoring of total hemoglobin concentration in the radial artery. The system includes a nanosecond laser operating in the near-IR spectral range and a sensitive optoacoustic probe designed for irradiating the radial artery through the skin and detecting optoacoustic signals induced in blood. Results of our studies indicate that parameters of optoacoustic waves induced in blood are dependent on total hemoglobin concentration. The data suggest that the optoacoustic system may be used for accurate, noninvasive, and continuous monitoring of total hemoglobin concentration.
{"title":"Noninvasive continuous optoacoustic monitor of total hemoglobin concentration","authors":"H. Brecht, Y. Petrov, D. Prough, D. Deyo, O. Hartrumpf, R. Esenaliev","doi":"10.1109/IEMBS.2002.1053286","DOIUrl":"https://doi.org/10.1109/IEMBS.2002.1053286","url":null,"abstract":"During surgery associated with rapid blood loss, rapid fluid administration and transfusion of packed red blood cells, measurement of total hemoglobin concentration provides necessary information to direct decisions regarding transfusion. However, measurement of total hemoglobin concentration currently requires collection of a blood sample and either transport to a laboratory or centrifugation at the bedside. Recently we proposed to use optoacoustic technique for noninvasive and continuous monitoring of total hemoglobin concentration. High resolution of the optoacoustic technique may provide accurate measurement of total hemoglobin concentration by detecting and analyzing optoacoustic signals induced by short optical pulses in blood circulating in arteries or veins. We designed, built, and tested in vitro and in preliminary in vivo experiments a portable optoacoustic system for monitoring of total hemoglobin concentration in the radial artery. The system includes a nanosecond laser operating in the near-IR spectral range and a sensitive optoacoustic probe designed for irradiating the radial artery through the skin and detecting optoacoustic signals induced in blood. Results of our studies indicate that parameters of optoacoustic waves induced in blood are dependent on total hemoglobin concentration. The data suggest that the optoacoustic system may be used for accurate, noninvasive, and continuous monitoring of total hemoglobin concentration.","PeriodicalId":60385,"journal":{"name":"中国地球物理学会年刊","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76090670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-01DOI: 10.1109/IEMBS.2002.1106547
J. Zwischenberger, Dongfong Wang, S. Alpard, C. Savage, D. Deyo, F. Schmalstieg, A. Bidani
Arteriovenous carbon dioxide removal (AVCO/sub 2/R) by a low-resistance gas exchanger in a simple arteriovenous shunt is capable of achieving near total CO/sub 2/ removal and lung rest during acute respiratory distress syndrome (ARDS). We evaluated AVCO/sub 2/R effect on a LD/sub 50/ smoke/burn (36 breath, 40% III/spl deg/ TBSA) ARDS model in a prospective, randomized, controlled, unblinded 7-day outcomes study of ventilator free days and survival. All AVCO/sub 2/R sheep survived, while only 2 SHAM animals survived the 7-day study. AVCO/sub 2/R had 2.4 ventilator dependent days versus 6.5 days with SHAM. For our initial patient experience, 5 adults in unresponsive, severe ARDS were successfully cannulated for AVCO/sub 2/R at bedside and completed the 72-h trial and 3/5 patients were discharged. AVCO/sub 2/R removed approximately 70% of CO/sub 2/. Changes in ventilator parameters from baseline to 48 h included a decrease in tidal volume, peak inspiratory pressure, minute ventilation, and respiratory rate. Next, a before-after study of AVCO/sub 2/R was performed on 8 subjects with ARDS. PaCO/sub 2/ decreased significantly despite a decrease in minute ventilation from baseline and normalization of pH. We propose the normalization of CO/sub 2/ and decreased minute ventilation allows amelioration of the pathophysiology of ARDS.
{"title":"Arterio venous carbon dioxide removal (AVCO/sub 2/R) for severe respiratory failure","authors":"J. Zwischenberger, Dongfong Wang, S. Alpard, C. Savage, D. Deyo, F. Schmalstieg, A. Bidani","doi":"10.1109/IEMBS.2002.1106547","DOIUrl":"https://doi.org/10.1109/IEMBS.2002.1106547","url":null,"abstract":"Arteriovenous carbon dioxide removal (AVCO/sub 2/R) by a low-resistance gas exchanger in a simple arteriovenous shunt is capable of achieving near total CO/sub 2/ removal and lung rest during acute respiratory distress syndrome (ARDS). We evaluated AVCO/sub 2/R effect on a LD/sub 50/ smoke/burn (36 breath, 40% III/spl deg/ TBSA) ARDS model in a prospective, randomized, controlled, unblinded 7-day outcomes study of ventilator free days and survival. All AVCO/sub 2/R sheep survived, while only 2 SHAM animals survived the 7-day study. AVCO/sub 2/R had 2.4 ventilator dependent days versus 6.5 days with SHAM. For our initial patient experience, 5 adults in unresponsive, severe ARDS were successfully cannulated for AVCO/sub 2/R at bedside and completed the 72-h trial and 3/5 patients were discharged. AVCO/sub 2/R removed approximately 70% of CO/sub 2/. Changes in ventilator parameters from baseline to 48 h included a decrease in tidal volume, peak inspiratory pressure, minute ventilation, and respiratory rate. Next, a before-after study of AVCO/sub 2/R was performed on 8 subjects with ARDS. PaCO/sub 2/ decreased significantly despite a decrease in minute ventilation from baseline and normalization of pH. We propose the normalization of CO/sub 2/ and decreased minute ventilation allows amelioration of the pathophysiology of ARDS.","PeriodicalId":60385,"journal":{"name":"中国地球物理学会年刊","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91207597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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