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Flow volume loop

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https://www.readbyqxmd.com/read/28047932/tu-h-campus-iep3-02-neurovascular-4d-parametric-imaging-using-co-registration-of-biplane-dsa-sequences-with-3d-vascular-geometry-obtained-from-cone-beam-ct
#1
A Balasubramoniam, D Bednarek, S Rudin, C Ionita
PURPOSE: To create 4D parametric images using biplane Digital Subtraction Angiography (DSA) sequences co-registered with the 3D vascular geometry obtained from Cone Beam-CT (CBCT). METHODS: We investigated a method to derive multiple 4D Parametric Imaging (PI) maps using only one CBCT acquisition. During this procedure a 3D-DSA geometry is stored and used subsequently for all 4D images. Each time a biplane DSA is acquired, we calculate 2D parametric maps of Bolus Arrival Time (BAT), Mean Transit Time (MTT) and Time to Peak (TTP)...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28043677/pressure-volume-loop-derived-cardiac-indices-during-dobutamine-stress-a-step-towards-understanding-limitations-in-cardiac-output-in-children-with-hypoplastic-left-heart-syndrome
#2
James Wong, Kuberan Pushparajah, Adelaide de Vecchi, Bram Ruijsink, Gerald F Greil, Tarique Hussain, Reza Razavi
BACKGROUND: Children with a single systemic right ventricle, such as in hypoplastic left heart syndrome (HLHS), frequently experience reduced exercise capacity. Elucidating the causes could help with optimising treatment strategies. METHODS: Prospective data from 10 consecutive symptomatic patients with HLHS undergoing clinical cardiac magnetic resonance with catheterisation (XMR) were analysed. Mean age 8.6years (range 3.5-11.6years), mean time since Fontan completion 5...
December 22, 2016: International Journal of Cardiology
https://www.readbyqxmd.com/read/28040707/stridor-secondary-to-a-subglottic-neuroendocrine-tumour
#3
Daniel W Scholfield, S Virk Jagdeep, Paul Stimpson
Large cell neuroendocrine carcinoma is a rare high-grade neuroendocrine neoplasm of the larynx, that exhibits particularly aggressive behaviour. We present a case of a 42-year-old patient with progressive dyspnoea and biphasic stridor, initially treated as asthma and resulting in delayed definitive management. Flow volume loops demonstrated narrowed inspiratory and expiratory flow volume loops. Subsequent CT neck and thorax indicated a mass arising from the subglottis and the patient proceeded to microlaryngoscopy and trans-oral CO2 laser debulking...
December 30, 2016: QJM: Monthly Journal of the Association of Physicians
https://www.readbyqxmd.com/read/28029367/on-the-feasibility-to-conduct-gradient-liquid-chromatography-separations-in-narrow-bore-columns-at-pressures-up-to-2000bar
#4
Ruben De Pauw, Tim Swier, Bart Degreef, Gert Desmet, Ken Broeckhoven
The limits in operating pressures are extended for narrow-bore columns in gradient elution up to 2000bar. As the required pumps for these pressures are incompatible with common chromatographic solvents and are not suitable to apply a mobile phase composition gradient, a mobile phase delivery and injection system is described and experimentally validated which allows to use any possible chromatographic solvent in isocratic and gradient elution. The mobile phase delivery and injection system also allows to perform multiple separations without the need to depressurize the column...
October 6, 2016: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28026740/comparative-hemodynamic-effects-of-contemporary-percutaneous-mechanical-circulatory-support-devices-in-a-porcine-model-of-acute-myocardial-infarction
#5
Brian R Weil, Filip Konecny, Gen Suzuki, Vijay Iyer, John M Canty
OBJECTIVES: The aim of this study was to directly compare the hemodynamic effects of 2 contemporary percutaneous mechanical circulatory support devices in a porcine model of acute myocardial infarction. BACKGROUND: Percutaneous support devices offer the ability to unload the ischemic left ventricle, but the comparative hemodynamic effects of contemporary platforms are unclear. METHODS: Yorkshire swine (mean weight 76 ± 2 kg; n = 7) were instrumented with a left ventricular (LV) pressure-volume (PV) catheter and subjected to a 2-h coronary occlusion...
November 28, 2016: JACC. Cardiovascular Interventions
https://www.readbyqxmd.com/read/27987598/role-of-vessel-to-prosthesis-size-mismatch-in-venous-valve-performance
#6
Wei-Hsin Tien, Xuefeng Zhao, Henry Y Chen, Zachary C Berwick, Joshua F Krieger, Sean Chambers, Dana Dabiri, Ghassan S Kassab
BACKGROUND: Efforts to treat chronic venous insufficiency have focused on the development of prosthetic venous valves. The role of prosthetic valve-to-vessel size matching has not been determined. The purpose of this investigation was to assess the effect of size mismatching on venous valve function and to establish a mismatch limit that affects valve hemodynamic performance and venous wall stress to improve future valve designs and implants. METHODS: Flow dynamics of prosthetic venous valves were studied in vitro using a pulse duplicator flow loop...
January 2017: Journal of Vascular Surgery. Venous and Lymphatic Disorders
https://www.readbyqxmd.com/read/27982272/cardiopulmonary-exercise-test-background-applicability-and-interpretation
#7
Artur Haddad Herdy, Luiz Eduardo Fonteles Ritt, Ricardo Stein, Claudio Gil Soares de Araújo, Mauricio Milani, Romeu Sérgio Meneghelo, Almir Sérgio Ferraz, Carlos Hossri, Antonio Eduardo Monteiro de Almeida, Miguel Morita Fernandes-Silva, Salvador Manoel Serra
Cardiopulmonary exercise test (CPET) has been gaining importance as a method of functional assessment in Brazil and worldwide. In its most frequent applications, CPET consists in applying a gradually increasing intensity exercise until exhaustion or until the appearance of limiting symptoms and/or signs. The following parameters are measured: ventilation; oxygen consumption (VO2); carbon dioxide production (VCO2); and the other variables of conventional exercise testing. In addition, in specific situations, pulse oximetry and flow-volume loops during and after exertion are measured...
November 2016: Arquivos Brasileiros de Cardiologia
https://www.readbyqxmd.com/read/27929571/an-unusual-mediastinal-mass
#8
J Hardy, A R Jeyabalan, N Bhatt, A R Medford
We report a case of a mediastinal mass indenting the left lateral tracheal wall of a 35-year-old male who presented with weight loss, cough and breathlessness. Flow volume loop and thyroid function tests were normal and thyroid peroxidase antibodies were negative. Technetium scintigraphy and positron emission tomography both showed no uptake. Endobronchial ultrasound-guided fine needle aspiration confirmed ectopic mediastinal thyroid tissue. Mediastinal ectopic thyroid tissue is very rare. Most patients are asymptomatic and euthyroid with positive signals on scintigraphy...
June 2016: Journal of the Royal College of Physicians of Edinburgh
https://www.readbyqxmd.com/read/27890535/partial-hepatectomy-hemodynamics-changes-experimental-data-explained-by-closed-loop-lumped-modeling
#9
Chloe Audebert, Mohamed Bekheit, Petru Bucur, Eric Vibert, Irene E Vignon-Clementel
The liver function may be degraded after partial liver ablation surgery. Adverse liver hemodynamics have been shown to be associated to liver failure. The link between these hemodynamics changes and ablation size is however poorly understood. This article proposes to explain with a closed-loop lumped model the hemodynamics changes observed during twelve surgeries in pigs. The portal venous tree is modeled with a pressure-dependent variable resistor. The variables measured, before liver ablation, are used to tune the model parameters...
January 4, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/27865733/systolic-and-diastolic-unloading-by-mechanical-support-of-the-acute-vs-the-chronic-pressure-overloaded-right-ventricle
#10
Tom Verbelen, Daniel Burkhoff, Keiichiro Kasama, Marion Delcroix, Filip Rega, Bart Meyns
BACKGROUND: Right ventricular (RV) mechanical support is well described in cases of sudden increase in RV afterload. In cases of chronic RV pressure overload (e.g., pulmonary arterial hypertension), it has rarely been described. METHODS: The pulmonary artery was banded in 18 sheep. In the acute group (n = 9), we immediately implanted a Synergy Pocket Micro-Pump. Blood was withdrawn from the right atrium to the pulmonary artery. In the chronic group (n = 9), this pump was implanted 8 weeks after banding...
October 17, 2016: Journal of Heart and Lung Transplantation
https://www.readbyqxmd.com/read/27754715/the-extracellular-c-loop-domain-plays-an-important-role-in-the-cell-adhesion-function-of-aquaporin-0
#11
Yosuke Nakazawa, Mikako Oka, Megumi Funakoshi-Tago, Hiroomi Tamura, Makoto Takehana
PURPOSE: Although aquaporin 0 (AQP0) is a member of the AQP family, it has limited water permeability compared with other members. AQP0 may also have cell adhesion-related functions, but the evidence is still limited. Here, we studied the relationship of AQP0 to cell adhesion and determined the region required for cell adhesion. METHODS: L-cell fibroblasts stably expressing AQP0 or AQP1 (L-AQP0 or L-AQP1) were established. One group of cells was stained with CellTracker Red and cultured into a confluent monolayer, whereas the other group was loaded with CellTracker Blue and seeded over the monolayer...
October 18, 2016: Current Eye Research
https://www.readbyqxmd.com/read/27692152/respiratory-pattern-in-a-fshd-pediatric-population
#12
Federica Trucco, Marina Pedemonte, Chiara Fiorillo, Paola Tacchetti, Giacomo Brisca, Claudio Bruno, Carlo Minetti
Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant inherited disorder characterized by selective weakness of face and upper arms and girdle. Respiratory involvement in FSHD has been described mainly in the most severely affected patients. In this work we tested the respiratory function by spirometry in 12 patients affected by FSHD with onset before 18 years. Spirometry results were correlated with motor involvement and compared to aged matched group of Becker patients. Of note FSHD patients present a peculiar pattern characterized by a flat shape in flow-volume loop...
October 2016: Respiratory Medicine
https://www.readbyqxmd.com/read/27620287/ventilator-related-causes-of-lung-injury-the-mechanical-power
#13
L Gattinoni, T Tonetti, M Cressoni, P Cadringher, P Herrmann, O Moerer, A Protti, M Gotti, C Chiurazzi, E Carlesso, D Chiumello, M Quintel
PURPOSE: We hypothesized that the ventilator-related causes of lung injury may be unified in a single variable: the mechanical power. We assessed whether the mechanical power measured by the pressure-volume loops can be computed from its components: tidal volume (TV)/driving pressure (∆P aw), flow, positive end-expiratory pressure (PEEP), and respiratory rate (RR). If so, the relative contributions of each variable to the mechanical power can be estimated. METHODS: We computed the mechanical power by multiplying each component of the equation of motion by the variation of volume and RR: [Formula: see text]where ∆V is the tidal volume, ELrs is the elastance of the respiratory system, I:E is the inspiratory-to-expiratory time ratio, and R aw is the airway resistance...
October 2016: Intensive Care Medicine
https://www.readbyqxmd.com/read/27600131/protocolized-resuscitation-of-burn-patients
#14
REVIEW
Leopoldo C Cancio, Jose Salinas, George C Kramer
Fluid resuscitation of burn patients is commonly initiated using modified Brooke or Parkland formula. The fluid infusion rate is titrated up or down hourly to maintain adequate urine output and other endpoints. Over-resuscitation leads to morbid complications. Adherence to paper-based protocols, flow sheets, and clinical practice guidelines is associated with decreased fluid resuscitation volumes and complications. Computerized tools assist providers. Although completely autonomous closed-loop control of resuscitation has been demonstrated in animal models of burn shock, the major advantages of open-loop and decision-support systems are identifying trends, enhancing situational awareness, and encouraging burn team communication...
October 2016: Critical Care Clinics
https://www.readbyqxmd.com/read/27582339/prototype-development-of-an-implantable-compliance-chamber-for-a-total-artificial-heart
#15
Stephanie Schmitz, Kristin Unthan, Marc Sedlaczek, Felix Wald, Thomas Finocchiaro, Sotirios Spiliopoulos, Reiner Koerfer, Ulrich Steinseifer
At our institute a total artificial heart is being developed. It is directly actuated by a linear drive in between two ventricles, which comprise membranes to separate the drive and blood flow. A compliance chamber (CC) is needed to reduce pressure peaks in the ventricles and to increase the pump capacity. Therefore, the movement of the membrane is supported by applying a negative pressure to the air volume inside the drive unit. This study presents the development of the implantable CC which is connected to the drive unit of the total artificial hearts (TAH)...
September 1, 2016: Artificial Organs
https://www.readbyqxmd.com/read/27575552/relation-of-concavity-in-the-expiratory-flow-volume-loop-to-dynamic-hyperinflation-during-exercise-in-copd
#16
Janos Varga, Richard Casaburi, Shuyi Ma, Ariel Hecht, David Hsia, Attila Somfay, Janos Porszasz
Active expiration during exercise can increase intrathoracic pressure yielding concavity in the expiratory flow-volume loop in COPD. We investigated the relationship between this concavity and dynamic hyperinflation (DH). 17 COPD patients (FEV1: 38±10%pred, GOLD stage 3-4) and 12 healthy subjects performed cycle ergometer incremental exercise. Expiratory limb of the spontaneous flow-volume loop was analyzed breath-by-breath using a geometric approach (rectangular area ratio (RAR), Respir. Med., 104(3):389-96, 2010)...
August 26, 2016: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/27571389/mixing-and-mass-transfer-in-a-pilot-scale-u-loop-bioreactor
#17
Leander A H Petersen, John Villadsen, Sten B Jørgensen, Krist V Gernaey
A system capable of handling a large volumetric gas fraction while providing a high gas to liquid mass transfer is a necessity if the metanotrophic bacterium Methylococcus capsulatus is to be used in single cell protein (SCP) production. In this study, mixing time and mass transfer coefficients were determined in a 0.15 m(3) forced flow U-loop fermenter of a novel construction. The effect on the impeller drawn power when a gas was introduced into the system was also studied. Mixing time decreased and mass transfer increased with increasing volumetric liquid flow rate and specific power input...
February 2017: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/27553595/can-pfts-differentiate-pvfmd-from-subglottic-stenosis
#18
Liuba Soldatova, Candace Hrelec, Laura Matrka
OBJECTIVE: To determine if the results of routine spirometry and flow volume loops (Pulmonary Function Tests (PFTs)) can be used to distinguish Paradoxic Vocal Fold Movement Disorder (PVFMD) from Subglottic Stenosis (SGS). METHODS: PFT records and medical history of 49 patients with diagnosis of PVFMD and 39 patients with SGS were compared. Groups were then subdivided to compare PFTs in patients with and without smoking history or lung disease. RESULTS: Peak expiratory flow rate (PEFR) and Expiratory Disproportion Index (ratio of forced expiratory volume in 1 second (FEV1) over PEFR (FEV1/PEFR)) were both significantly different between patients with SGS and those with PVFMD (p<0...
December 2016: Annals of Otology, Rhinology, and Laryngology
https://www.readbyqxmd.com/read/27544288/comparison-of-the-performance-of-a-sutureless-bioprosthesis-with-two-pericardial-stented-valves-on-small-annuli-an-in%C3%A2-vitro-study
#19
Giordano Tasca, Riccardo Vismara, Andrea Mangini, Claudia Romagnoni, Monica Contino, Alberto Redaelli, Gianfranco Beniamino Fiore, Carlo Antona
BACKGROUND: Aortic valve replacement has evolved recently with the development of the sutureless bioprosthesis. One such valve is the Perceval bioprosthesis, which is built by mounting leaflets of bovine pericardium to a thin stent; this approach has the potential to provide an excellent fluid dynamic performance. We undertook an in vitro study to compare the hydrodynamic performance of the sutureless bioprosthesis with two standard pericardial stented bioprostheses (Crown and Magna)...
January 2017: Annals of Thoracic Surgery
https://www.readbyqxmd.com/read/27542407/cardiac-neural-crest-ablation-results-in-early-endocardial-cushion-and-hemodynamic-flow-abnormalities
#20
Pei Ma, Shi Gu, Ganga H Karunamuni, Michael W Jenkins, Michiko Watanabe, Andrew M Rollins
Cardiac neural crest cell (CNCC) ablation creates congenital heart defects (CHDs) that resemble those observed in many syndromes with craniofacial and cardiac consequences. The loss of CNCCs causes a variety of great vessel defects, including persistent truncus arteriosus and double-outlet right ventricle. However, because of the lack of quantitative volumetric measurements, less severe defects, such as great vessel size changes and valve defects, have not been assessed. Also poorly understood is the role of abnormal cardiac function in the progression of CNCC-related CHDs...
November 1, 2016: American Journal of Physiology. Heart and Circulatory Physiology
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