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Harte SE, Wiseman J, Wang Y, Smith AR, Yang CC, Helmuth M, Kreder K, Kruger GH, Gillespie BW, Amundsen C, Kirkali Z, Lai HH. Experimental Pain and Auditory Sensitivity in Overactive Bladder Syndrome: A Symptoms of the Lower Urinary Tract Dysfunction Research Network (LURN) Study. J Urol 2022; 207:161-171. [PMID: 34428922 PMCID: PMC9237822 DOI: 10.1097/ju.0000000000002147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/22/2021] [Indexed: 11/26/2022]
Abstract
PURPOSE The objective of this study was to investigate the presence of nonbladder sensory abnormalities in participants with overactive bladder syndrome (OAB). MATERIALS AND METHODS Symptoms of Lower Urinary Tract Dysfunction Research Network (LURN) study participants with OAB symptoms and controls were recruited from 6 U.S. tertiary referral centers. Quantitative sensory testing (QST) was performed to determine pressure pain sensitivity at the thumbnail bed and auditory sensitivity. Fixed and mixed effect multivariable linear regressions and Weibull models were used to compare QST responses between groups. Pearson correlations were used to assess the relationship between QST measures. Associations between QST and self-reported symptoms were explored with linear regression. RESULTS A total of 297 participants were analyzed (191 OAB, 106 controls; 76% white, 51% male). OAB cases were older than controls (57.4 vs 52.2 years, p=0.015). No significant differences in experimental thumbnail (nonbladder) pain or auditory sensitivity were detected between OAB cases and controls. Correlations between pressure and auditory derived metrics were weak to moderate overall for both groups, with some significantly stronger correlations for cases. Exploratory analyses indicated increased pressure pain and auditory sensitivity were modestly associated with greater self-reported bladder pain and pain interference with physical function. CONCLUSIONS As a group, no significant differences between OAB cases and controls were observed in experimental nonbladder pain or auditory sensitivity during QST. Associations between QST outcomes and clinical pain raise the possibility of centrally mediated sensory amplification in some individuals with OAB.
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Affiliation(s)
- Steven E. Harte
- Chronic Pain and Fatigue Research Center, Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Jon Wiseman
- Arbor Research Collaborative for Health, Ann Arbor, MI USA
| | - Ying Wang
- Department of Anesthesia, Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | | | - Claire C. Yang
- Department of Urology, University of Washington, Seattle, WA, 98195-6510 USA
| | | | - Karl Kreder
- Department of Urology, University of Iowa, Iowa City, IA, USA
| | - Grant H. Kruger
- Chronic Pain and Fatigue Research Center, Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | | | - Cindy Amundsen
- Department of Obstetrics and Gynecology, Duke University, Durham, North Carolina, USA
| | - Ziya Kirkali
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - H. Henry Lai
- Division of Urologic Surgery, Departments of Surgery and Anesthesiology, Washington University School of Medicine, St Louis, MO, USA
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Dabiri D, Harper DE, Kapila Y, Kruger GH, Clauw DJ, Harte S. Applications of sensory and physiological measurement in oral-facial dental pain. Spec Care Dentist 2018; 38:395-404. [PMID: 30194771 PMCID: PMC6282998 DOI: 10.1111/scd.12323] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 08/01/2018] [Accepted: 08/05/2018] [Indexed: 12/01/2022]
Abstract
Dentists regularly employ a variety of self‐report and sensory techniques to aid in the diagnosis and treatment of tooth‐related disease. Many of these techniques leverage principles borrowed from psychophysics, the quantitative measurement of the relationship between stimuli and evoked sensations, which falls under the larger umbrella of quantitative sensory testing (QST). However, most clinicians fail to meet the bar for what could be considered quantitative sensory testing, and instead focus on qualitative and dichotomous “yes/no” aspects of sensory experience. With our current subjective measurements for pain assessments, diagnosis and treatment of dental pain in young children and individuals (any age) with severe cognitive impairment rely extensively on third‐party observations. Consequently, the limitation of inadequate pain diagnosis can lead to poor pain management. In this review, it discusses mechanisms that underlie acute and chronic dental pain. It details the measurement of somatosensory responses and pulpal blood flow as objective measures of tooth health and pain. It proposes that bridging these varied methodologies will significantly improve diagnosis and treatment of orofacial pain and pathology. It concludes that improving the precision of sensory measurements could yield important improvements in diagnostic challenges in pulpal pathology for noncommunicative and cognitively impaired individuals.
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Affiliation(s)
- Darya Dabiri
- Chronic Pain & Fatigue Research Center, Department of Anesthesiology, University of Michigan Medicine, Ann Arbor, Michigan
| | - Daniel E Harper
- Chronic Pain & Fatigue Research Center, Department of Anesthesiology, University of Michigan Medicine, Ann Arbor, Michigan
| | - Yvonne Kapila
- Division of Periodontology, Department of Orofacial Sciences, University of California San Francisco, San Francisco, California
| | - Grant H Kruger
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan
| | - Daniel J Clauw
- Chronic Pain & Fatigue Research Center, Department of Anesthesiology, University of Michigan Medicine, Ann Arbor, Michigan
| | - Steven Harte
- Chronic Pain & Fatigue Research Center, Department of Anesthesiology, University of Michigan Medicine, Ann Arbor, Michigan
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Treister R, Lawal OD, Shecter JD, Khurana N, Bothmer J, Field M, Harte SE, Kruger GH, Katz NP. Accurate pain reporting training diminishes the placebo response: Results from a randomised, double-blind, crossover trial. PLoS One 2018; 13:e0197844. [PMID: 29795665 PMCID: PMC5993117 DOI: 10.1371/journal.pone.0197844] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Accepted: 04/25/2018] [Indexed: 12/01/2022] Open
Abstract
Analgesic trials frequently fail to demonstrate efficacy of drugs known to be efficacious. Poor pain reporting accuracy is a possible source for this low essay-sensitivity. We report the effects of Accurate-Pain-Reporting-Training (APRT) on the placebo response in a trial of Pregabalin for painful-diabetic-neuropathy. The study was a two-stage randomized, double-blind trial: In Stage-1 (Training) subjects were randomized to APRT or No-Training. The APRT participants received feedback on the accuracy of their pain reports in response to mechanical stimuli, measured by R-square score. In Stage-2 (Evaluation) all subjects entered a placebo-controlled, cross-over trial. Primary (24-h average pain intensity) and secondary (current, 24-h worst, and 24-h walking pain intensity) outcome measures were reported. Fifty-one participants completed the study. APRT patients (n = 28) demonstrated significant (p = 0.036) increases in R-square scores. The APRT group demonstrated significantly (p = 0.018) lower placebo response (0.29 ± 1.21 vs. 1.48 ± 2.21, mean difference ± SD = -1.19±1.73). No relationships were found between the R-square scores and changes in pain intensity in the treatment arm. In summary, our training successfully increased pain reporting accuracy and resulted in a diminished placebo response. Theoretical and practical implications are discussed.
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Affiliation(s)
- Roi Treister
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Faculty of Social Welfare and Health Sciences, University of Haifa, Haifa, Israel
- Analgesic Solutions, Natick, Massachusetts, United States of America
- * E-mail:
| | | | | | - Nevil Khurana
- Analgesic Solutions, Natick, Massachusetts, United States of America
| | | | | | - Steven E. Harte
- Chronic Pain and Fatigue Research Center, Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Grant H. Kruger
- Chronic Pain and Fatigue Research Center, Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Nathaniel P. Katz
- Analgesic Solutions, Natick, Massachusetts, United States of America
- Department of Anaesthesiology and Perioperative Medicine, Tufts University School of Medicine, Boston, Massachusetts, United States of America
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Kruger GH, Shanks A, Kheterpal S, Tremper T, Chiang CJ, Freundlich RE, Blum JM, Shih AJ, Tremper KK. Influence of non-invasive blood pressure measurement intervals on the occurrence of intra-operative hypotension. J Clin Monit Comput 2017; 32:699-705. [PMID: 28965158 DOI: 10.1007/s10877-017-0065-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 09/20/2017] [Indexed: 10/18/2022]
Abstract
The American Society of Anesthesiologists Standards for Basic Monitoring recommends blood pressure (BP) measurement every 5 min. Research has shown distractions or technical factors can cause prolonged measurement intervals exceeding 5 min. We investigated the relationship between prolonged non-invasive BP (NIBP) measurement interval and the incidence of hypotension, detected post-interval. Our secondary outcome was to determine independent predictors of these prolonged NIBP measurement intervals. Retrospective data were analyzed from 139,509 general anesthesia cases from our institution's Anesthesia Information Management System (AIMS). Absolute hypotension (AH) was defined a priori as a systolic BP < 80 mmHg and relative hypotension (RH) was defined as a 40% decrease in systolic BP from the preoperative baseline. Odds ratios (OR) with 95% confidence intervals and Pearson's Chi square Test reported the association of prolonged NIBP measurement intervals on hypotension detected post-NIBP measurement interval. Logistic regression models were developed to determine independent predictors of NIBP measurement intervals. The analysis revealed that NIBP measurement intervals greater than 6 and 10 min are associated with an approximately four times higher incidence of a patient transitioning into hypotension (AH/RH > 6 min OR 4.0 / 3.6; AH/RH > 10 min OR 4.3 / 3.9; p < 0.001). A key finding was that the "> 10-minute AH model" indicated that age 41-80, increased co-morbidity profile, obesity and turning (repositioning) of the operative room table were significant predictors of prolonged NIBP measurement intervals (p < 0.001). While we do not suggest NIBP measurement intervals cause hypotension, intervals greater than 6 and 10 min are associated with a fourfold increase in the propensity of an undetected transition into both RH or AH. These data support current monitoring guidelines.
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Affiliation(s)
- Grant H Kruger
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA.
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, USA.
| | - Amy Shanks
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, USA
| | - Sachin Kheterpal
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, USA
| | - Tyler Tremper
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, USA
| | | | - Robert E Freundlich
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - James M Blum
- Critical Care Anesthesiology, Emory University School of Medicine, Atlanta, GA, USA
| | - Albert J Shih
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Kevin K Tremper
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, USA
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Pitre JJ, Koziol LB, Kruger GH, Vollmer A, Ophir J, Ammann JJ, Weitzel WF, Bull JL. Design and Testing of a Single-Element Ultrasound Viscoelastography System for Point-of-Care Edema Quantification. Ultrasound Med Biol 2016; 42:2209-2219. [PMID: 27222246 PMCID: PMC4983502 DOI: 10.1016/j.ultrasmedbio.2016.04.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 03/08/2016] [Accepted: 04/18/2016] [Indexed: 06/05/2023]
Abstract
Management of fluid overload in patients with end-stage renal disease represents a unique challenge to clinical practice because of the lack of accurate and objective measurement methods. Currently, peripheral edema is subjectively assessed by palpation of the patient's extremities, ostensibly a qualitative indication of tissue viscoelastic properties. New robust quantitative estimates of tissue fluid content would allow clinicians to better guide treatment, minimizing reactive treatment decision making. Ultrasound viscoelastography (UVE) can be used to estimate strain in viscoelastic tissue, deriving material properties that can help guide treatment. We are developing and testing a simple, low-cost UVE system using a single-element imaging transducer that is simpler and less computationally demanding than array-based systems. This benchtop validation study tested the feasibility of using the UVE system by measuring the mechanical properties of a tissue-mimicking material under large strains. We generated depth-dependent creep curves and viscoelastic parameter maps of time constants and elastic moduli for the Kelvin model of viscoelasticity. During testing, the UVE system performed well, with mean UVE-measured strain matching standard mechanical testing with maximum absolute errors ≤4%. Motion tracking revealed high correlation and signal-to-noise ratios, indicating that the system is reliable.
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Affiliation(s)
- John J Pitre
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Leo B Koziol
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA; Department of Veterans Affairs Medical Center, Ann Arbor, Michigan, USA
| | - Grant H Kruger
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA; Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan, USA; Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Alan Vollmer
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA; Department of Veterans Affairs Medical Center, Ann Arbor, Michigan, USA
| | - Jonathan Ophir
- Ultrasonics Laboratory, Department of Diagnostic and Interventional Imaging, University of Texas Medical School, Houston, Texas, USA
| | - Jean-Jacques Ammann
- Department of Physics, Universidad de Santiago, Santiago, Chile; G.E.A. Universitas SpA, Santiago, Chile
| | - William F Weitzel
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA; Department of Veterans Affairs Medical Center, Ann Arbor, Michigan, USA
| | - Joseph L Bull
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA.
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Becker DM, Tafoya CA, Becker SL, Kruger GH, Tafoya MJ, Becker TK. The use of portable ultrasound devices in low- and middle-income countries: a systematic review of the literature. Trop Med Int Health 2016; 21:294-311. [PMID: 26683523 DOI: 10.1111/tmi.12657] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVES To review the scientific literature pertaining to the use of hand-carried and hand-held ultrasound devices in low- and middle-income countries (LMIC), with a focus on clinical applications, geographical areas of use, the impact on patient management and technical features of the devices used. METHODS The electronic databases PubMed and Google Scholar were searched. No language or date restrictions were applied. Case reports and original research describing the use of hand-carried ultrasound devices in LMIC were included if agreed upon as relevant by two-reviewer consensus based on our predefined research questions. RESULTS A total of 644 articles were found and screened, and 36 manuscripts were included for final review. Twenty-seven studies were original research articles, and nine were case reports. Several reports describe the successful diagnosis and management of difficult, often life-threatening conditions, using hand-carried and hand-held ultrasound. These portable ultrasound devices have also been studied for cardiac screening exams, as well as a rapid triage tool in rural areas and after natural disaster. Most applications focus on obstetrical and abdominal complaints. Portable ultrasound may have an impact on clinical management in up to 70% of all cases. However, no randomised controlled trials have evaluated the impact of ultrasound-guided diagnosis and treatment in resource-constrained settings. The exclusion of articles published in journals not listed in the large databases may have biased our results. Our findings are limited by the lack of higher quality evidence (e.g. controlled trials). CONCLUSIONS Hand-carried and hand-held ultrasound is successfully being used to triage, diagnose and treat patients with a variety of complaints in LMIC. However, the quality of the current evidence is low. There is an urgent need to perform larger clinical trials assessing the impact of hand-carried ultrasound in LMIC.
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Affiliation(s)
- Dawn M Becker
- Department of Internal Medicine, St. Joseph Mercy Hospital Ann Arbor - St. Joseph Mercy Health System, Ann Arbor, MI, USA
| | | | - Sören L Becker
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland.,Institute of Medical Microbiology and Hygiene, Saarland University Medical Center, Homburg/Saar, Germany
| | - Grant H Kruger
- Department of Mechanical Engineering, College of Engineering, University of Michigan, Ann Arbor, MI, USA
| | | | - Torben K Becker
- Department of Critical Care Medicine, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
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Dodde RE, Kruger GH, Shih AJ. Design of Bioimpedance Spectroscopy Instrument With Compensation Techniques for Soft Tissue Characterization. J Med Device 2015; 9:0210011-210018. [PMID: 26029317 PMCID: PMC4410770 DOI: 10.1115/1.4029706] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Revised: 01/22/2015] [Indexed: 11/08/2022] Open
Abstract
Bioimpedance spectroscopy (BIS) has shown significant potential in many areas of medicine to provide new physiologic markers. Several acute and chronic diseases are accompanied by changes in intra- and extracellular fluid within various areas of the human body. The estimation of fluid in various body compartments is therefore a simple and convenient method to monitor certain disease states. In this work, the design and evaluation of a BIS instrument are presented and three key areas of the development process investigated facilitating the BIS measurement of tissue hydration state. First, the benefit of incorporating DC-stabilizing circuitry to the standard modified Howland current pump (MHCP) is investigated to minimize the effect of DC offsets limiting the dynamic range of the system. Second, the influence of the distance between the bioimpedance probe and a high impedance material is investigated using finite element analysis (FEA). Third, an analytic compensation technique is presented to minimize the influence of parasitic capacitance. Finally, the overall experimental setup is evaluated through ex vivo BIS measurements of porcine spleen tissue and compared to published results. The DC-stabilizing circuit demonstrated its ability to maintain DC offsets at less than 650 μV through 100 kHz while maintaining an output impedance of 1 MΩ from 100 Hz to 100 kHz. The proximity of a bioimpedance probe to a high impedance material such as acrylic was shown to increase measured impedance readings by a factor of 4x as the ratio of the distance between the sensing electrodes to the distance between the bioimpedance probe and acrylic reached 1:3. The average parasitic capacitance for the circuit presented was found to be 712 ± 128 pF, and the analytic compensation method was shown to be able to minimize this effect on the BIS measurements. Measurements of porcine spleen tissue showed close correlation with experimental results reported in published articles. This research presents the successful design and evaluation of a BIS instrument. Specifically, robust measurements were obtained by implementing a DC-stabilized current source, investigating probe-material proximity issues and compensating for parasitic capacitance. These strategies were shown to provide tissue measurements comparable with published literature.
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Affiliation(s)
- Robert E Dodde
- Stryker Corporation , 4100 E. Milham Avenue, Kalamazoo, MI 49001 e-mail:
| | - Grant H Kruger
- Mechanical Engineering, University of Michigan , 1031 H.H. Dow Building, 2350 Hayward Street, Ann Arbor, MI 48109 e-mail:
| | - Albert J Shih
- Mechanical Engineering, University of Michigan , 3001E EECS, 1301 Beal, Ann Arbor, MI 48109 e-mail:
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Weitzel WF, Hamilton J, Wang X, Bull JL, Vollmer A, Bowman A, Rubin J, Kruger GH, Gao J, Heung M, Rao P. Quantitative Lung Ultrasound Comet Measurement: Method and Initial Clinical Results. Blood Purif 2015; 39:37-44. [DOI: 10.1159/000368973] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
<b><i>Background/Aims:</i></b> Recently, ultrasound signals termed ‘lung water comets' associated with pulmonary edema have been correlated with adverse clinical events in dialysis patients. These comets fluctuate substantially during the ultrasound exam highlighting the need for objective quantitative measurement methods. <b><i>Methods:</i></b> We developed an image-processing algorithm for the detection and quantification of lung comets. Quantification measures included comet number (comet count) and the fraction of the ultrasound beams with comet findings (comet fraction). We used this algorithm in a pilot study in 20 stable dialysis outpatients to identify associations between ultrasound comets and clinical parameters including blood pressure (BP), percent blood volume reduction on dialysis (%BV), ejection fraction (EF), and ultrafiltration on dialysis (UF). <b><i>Results:</i></b> Positive findings included associations with lung comet measurements with pre-dialysis Diastolic BP (r = 0.534, p = 0.015), subject age (r = -0.446, p = 0.049), and a combination of EF and end dialysis %BV reduction (r = -0.585, p = 0.028). Comet fraction and comet count were closely correlated due to the inherent relationship between these two metrics (r = 0.973, p < 0.001). Negative findings included ultrasound comets that did not change from beginning to end of dialysis (p = 0.756), and were not significantly correlated with single dialysis treatment UF (p = 0.522), subject body weight (p = 0.208), or BMI (p = 0.358). <b><i>Conclusions:</i></b> Ultrasound signal processing methods may help quantify lung ultrasound comets. Additional findings include algorithmic lung comet measurement that did not change significantly during single dialysis sessions in these stable outpatients, but were associated with cardiovascular and fluid status parameters.
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Park DW, Kruger GH, Rubin JM, Hamilton J, Gottschalk P, Dodde RE, Shih AJ, Weitzel WF. Quantification of ultrasound correlation-based flow velocity mapping and edge velocity gradient measurement. J Ultrasound Med 2013; 32:1815-1830. [PMID: 24065263 DOI: 10.7863/ultra.32.10.1815] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
This study investigated the use of ultrasound speckle decorrelation- and correlation-based lateral speckle-tracking methods for transverse and longitudinal blood velocity profile measurement, respectively. By studying the blood velocity gradient at the vessel wall, vascular wall shear stress, which is important in vascular physiology as well as the pathophysiologic mechanisms of vascular diseases, can be obtained. Decorrelation-based blood velocity profile measurement transverse to the flow direction is a novel approach, which provides advantages for vascular wall shear stress measurement over longitudinal blood velocity measurement methods. Blood flow velocity profiles are obtained from measurements of frame-to-frame decorrelation. In this research, both decorrelation and lateral speckle-tracking flow estimation methods were compared with Poiseuille theory over physiologic flows ranging from 50 to 1000 mm/s. The decorrelation flow velocity measurement method demonstrated more accurate prediction of the flow velocity gradient at the wall edge than the correlation-based lateral speckle-tracking method. The novelty of this study is that speckle decorrelation-based flow velocity measurements determine the blood velocity across a vessel. In addition, speckle decorrelation-based flow velocity measurements have higher axial spatial resolution than Doppler ultrasound measurements to enable more accurate measurement of blood velocity near a vessel wall and determine the physiologically important wall shear.
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Affiliation(s)
- Dae Woo Park
- Department of Bioengineering, University of Pittsburgh, 567 Scaife Hall, 3550 Terrace St, Pittsburgh, PA 15213 USA.
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Harte SE, Mitra M, Ichesco EA, Halvorson ME, Clauw DJ, Shih AJ, Kruger GH. Development and validation of a pressure-type automated quantitative sensory testing system for point-of-care pain assessment. Med Biol Eng Comput 2013; 51:633-44. [PMID: 23381890 DOI: 10.1007/s11517-013-1033-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Accepted: 01/06/2013] [Indexed: 10/27/2022]
Abstract
Quantitative sensory testing (QST) can provide useful information about the underlying mechanisms involved in chronic pain. However, currently available devices typically employed suffer from operator-dependent effects, or are too cumbersome for routine clinical care. This paper presents the design and initial validation of a novel automated pressure-pain type QST platform, termed the multi-modal automated sensory testing (MAST) system. The MAST configuration presented consists of wireless, hand-held thumbnail pressure stimulators (with circular 10 mm² rubber tips) and graphical touch screen interface devices to manage the QST process and obtain patient feedback. Validation testing of the custom-designed force sensor showed a 1 % error for low forces increasing to 2 % error for larger loads up to 100 N (full-scale). Validation of the controller using three ramp rates (64, 248, and 496 kPa/s) and six pressures (32, 62, 124, 273, 620, and 1116 kPa) showed an overall mean error of 1.7 % for applied stimuli. Clinical evaluation revealed decreased pressure pain thresholds in chronic pain patients (98.07 ± SE 16.34 kPa) compared to pain free, healthy control subjects (259.88 ± SE 33.54 kPa, p = 0.001). The MAST system is portable and produces accurate, repeatable stimulation profiles indicating potential for point-of-care applications.
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Affiliation(s)
- Steven E Harte
- Department of Anesthesiology, Chronic Pain and Fatigue Research Center, University of Michigan Medical School, Ann Arbor, MI 48106, USA
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Wong P, Johnson KJ, Warner RL, Merz SI, Kruger GH, Weitzel WF. Performance of Biopsy Needle With Therapeutic Injection System to Prevent Bleeding Complications. J Med Device 2013; 7:110021-110027. [PMID: 23917874 DOI: 10.1115/1.4023274] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 11/06/2012] [Indexed: 11/08/2022] Open
Abstract
Renal disease is epidemic in the United States with approximately 8 × 106 people having chronic kidney disease. Renal biopsies are widely used to provide essential diagnostic information to physicians. However, the risk of bleeding complications possibly leading to life-threatening situations results in the contra-indication of biopsy in certain patient populations. Safer renal biopsies will allow more accurate diagnosis and better management of this epidemic health problem. We report the preclinical testing of a novel biopsy device called the therapeutic injection system (TIS). The device introduces a third stage to the standard two-stage side-cut percutaneous biopsy process. The third stage is designed to reduce bleeding complications by injecting a hemostatic plug at the time of biopsy. Laboratory evaluation and preliminary in vivo animal testing using an anticoagulated porcine model of the TIS and Bard Monopty® (Bard Medical, Covington, GA) control device were performed. The hemostatic material Gelfoam® (Pfizer, Brussels, Belgium) was selected as the active material comprising the hemostatic plugs. The performance of two composite plugs, one composed of polyvinyl alcohol (PVA) combined in 2:1 and 12:1 ratios with the hemostatic material, and one plug composed of 100[Formula: see text] hemostatic material were tested. Stroke sequence and hemostatic plug deployment were verified by sequential firing of the TIS biopsy needle into clear gelatin and ex vivo bovine kidney specimens. In vivo trials with porcine specimens revealed a significant reduction in blood loss (8.1 [Formula: see text] 3.9 ml, control versus 1.9 [Formula: see text] 1.6 ml, 12:1 PVA/hemostatic, TIS, [Formula: see text] = 0.01, [Formula: see text] = 6). The 100[Formula: see text] hemostatic plug showed a substantial and immediate reduction in blood loss (9.2 ml, control versus 0.0 ml, TIS, [Formula: see text] = 1). The prototype device was shown to work repeatedly and reliably in laboratory trials. Initial results show promise in this approach to control post biopsy bleeding. This solution maintains the simplicity and directness of the percutaneous approach, while not significantly changing the standard percutaneous biopsy procedure.
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Affiliation(s)
- Philip Wong
- MC3, Inc., 3526 West Liberty, Suite 100 , Ann Arbor, MI 48103 e-mail:
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Park DW, Kruger GH, Rubin JM, Hamilton J, Gottschalk P, Dodde RE, Shih AJ, Weitzel WF. In vivo vascular wall shear rate and circumferential strain of renal disease patients. Ultrasound Med Biol 2013; 39:241-52. [PMID: 23211936 PMCID: PMC3538941 DOI: 10.1016/j.ultrasmedbio.2012.08.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 08/23/2012] [Accepted: 08/25/2012] [Indexed: 05/16/2023]
Abstract
This study measures the vascular wall shear rate at the vessel edge using decorrelation based ultrasound speckle tracking. Results for nine healthy and eight renal disease subjects are presented. Additionally, the vascular wall shear rate and circumferential strain during physiologic pressure, pressure equalization and hyperemia are compared for five healthy and three renal disease subjects. The mean and maximum wall shear rates were measured during the cardiac cycle at the top and bottom wall edges. The healthy subjects had significantly higher mean and maximum vascular wall shear rate than the renal disease subjects. The key findings of this research were that the mean vascular wall shear rates and circumferential strain changes between physiologic pressure and hyperemia that was significantly different between healthy and renal disease subjects.
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Affiliation(s)
- Dae Woo Park
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48105, USA.
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Kruger GH, Dodde RE, Thelen B, Weitzel WF. Hand-held Ultrasound Device for Dialysis Vascular Access Volume Flow Monitoring. J Med Device 2012. [DOI: 10.1115/1.4026780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Kruger GH, Weitzel WF. Percutaneous Biopsy Device Design with Haemostatic Bleeding Control. J Med Device 2012. [DOI: 10.1115/1.4026782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Abstract
Intelligent medical displays have the potential to improve patient outcomes by integrating multiple physiologic signals, exhibiting high sensitivity and specificity, and reducing information overload for physicians. Research findings have suggested that information overload and distractions caused by patient care activities and alarms generated by multiple monitors in acute care situations, such as the operating room and the intensive care unit, may produce situations that negatively impact the outcomes of patients under anesthesia. This can be attributed to shortcomings of human-in-the-loop monitoring and the poor specificity of existing physiologic alarms. Modern artificial intelligence techniques (ie, intelligent software agents) are demonstrating the potential to meet the challenges of next-generation patient monitoring and alerting.
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Affiliation(s)
- Grant H Kruger
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI 48109-5048, USA.
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Gonzalez-Cota A, Kruger GH, Raghavan P, Reynolds PI. Computational Modeling and Prototyping of a Pediatric Airway Management Instrument. Anesth Analg 2010; 111:649-52. [DOI: 10.1213/ane.0b013e3181e5ea7c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Park DW, Richards MS, Rubin JM, Hamilton J, Kruger GH, Weitzel WF. Arterial elasticity imaging: comparison of finite-element analysis models with high-resolution ultrasound speckle tracking. Cardiovasc Ultrasound 2010; 8:22. [PMID: 20565833 PMCID: PMC2908573 DOI: 10.1186/1476-7120-8-22] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Accepted: 06/18/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The nonlinear mechanical properties of internal organs and tissues may be measured with unparalleled precision using ultrasound imaging with phase-sensitive speckle tracking. The many potential applications of this important noninvasive diagnostic approach include measurement of arterial stiffness, which is associated with numerous major disease processes. The accuracy of previous ultrasound measurements of arterial stiffness and vascular elasticity has been limited by the relatively low strain of nonlinear structures under normal physiologic pressure and the measurement assumption that the effect of the surrounding tissue modulus might be ignored in both physiologic and pressure equalized conditions. METHODS This study performed high-resolution ultrasound imaging of the brachial artery in a healthy adult subject under normal physiologic pressure and the use of external pressure (pressure equalization) to increase strain. These ultrasound results were compared to measurements of arterial strain as determined by finite-element analysis models with and without a surrounding tissue, which was represented by homogenous material with fixed elastic modulus. RESULTS Use of the pressure equalization technique during imaging resulted in average strain values of 26% and 18% at the top and sides, respectively, compared to 5% and 2%, at the top and sides, respectively, under physiologic pressure. In the artery model that included surrounding tissue, strain was 19% and 16% under pressure equalization versus 9% and 13% at the top and sides, respectively, under physiologic pressure. The model without surrounding tissue had slightly higher levels of strain under physiologic pressure compared to the other model, but the resulting strain values under pressure equalization were > 60% and did not correspond to experimental values. CONCLUSIONS Since pressure equalization may increase the dynamic range of strain imaging, the effect of the surrounding tissue on strain should be incorporated into models of arterial strain, particularly when the pressure equalization technique is used.
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Affiliation(s)
- Dae Woo Park
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
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van Rensburg L, Kruger H, Breytenbach J, Coetzee J, van der Merwe CF, van Aswegen G, Kruger GH. Immunogold localization and quantification of cellular and subcellular abscisic acid, prior to and during drought stress. Biotech Histochem 1996; 71:38-43. [PMID: 9138527 DOI: 10.3109/10520299609117129] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
An immunogold labeling procedure and experimental data are presented, which demonstrate that antibodies produced against a bovine serum albumin-abscisic acid conjugate can be used both to characterize the cellular and subcellular localization of abscisic acid (ABA), and to permit quantitative comparisons of this hormone in the subcellular compartments prior to and at times of drought stress. At the control leaf water potential (approximately -0.45 MPa), a quantitatively similar positive labeling pattern was observed in the chloroplasts and apoplast. A twofold drought stress-induced increase in the apoplastic ABA concentration was observed in the drought stressed leaf tissue (i.e., at a leaf water potential of approximately -1.55 MPa), while the ABA concentration in the chloroplasts did not differ from that of the controls. Three histochemical controls and the physiological observations validated the specificity of the procedure. Based on the labeling patterns we observed and literature cited, the validity of the hypothesis that drought stress induces a release of chloroplastic ABA is questioned. We interpreted our results as providing indirect evidence for a drought stress-induced root source origin for the increased apoplastic ABA concentrations.
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Affiliation(s)
- L van Rensburg
- Department of Plant and Soil Sciences, Potchefstroom University for Christian Higher Education, Republic of South Africa
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