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Topic: Elastance


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AAP

In the News (Sat 2 Jun 12)

  
  Elastance of the Pleural Space: A Predictor for the Outcome of Pleurodesis in Patients with Malignant Pleural Effusion ...
Elastance of the Pleural Space: A Predictor for the Outcome of Pleurodesis in Patients with Malignant Pleural Effusion -- Lan et al.
Elastance of the Pleural Space: A Predictor for the Outcome of Pleurodesis in Patients with Malignant Pleural Effusion
Therefore, it is not surprising that elastance is a
www.annals.org /cgi/content/full/126/10/768   (3510 words)

  
 Heart Dynamics
The time-varying elastance model requires both ventricular volume and pressure to be measured during an ejecting beat, and therefore is a measure of both ventricular contractility and arterial properties.
This new analytical function also permits computation of ventricular elastance as a true differential by taking the partial derivative of pressure divided by the partial derivative of volume.
The resulting ventricular elastance curves are virtually independent of preload or arterial afterload, and reflect the contractile state of the ventricle (Palladino et al.,1998).
www.trincoll.edu /~palladin/JPresearch/heartdynamics/heartdynamics.htm   (531 words)

  
 Figure 2. Elastance of left ventricle over a cardiac cycle   (Site not responding. Last check: 2007-09-10)
Illustrated is the elastance (stiffness) of the left ventricle over a cardiac cycle in a 60 kg person, as seen in a normal person under resting conditions, a person with a maximally contractile ventricle, and a person with profound beta blockade or congestive heart failure.
With maximal contractility, elastance rises more quickly than normal, and maximal stiffness, at end-systole, is twice the normal value.
The elastance during diastole is lowest under conditions of maximal contractility, at least in this example.
www.acssurgery.com /wnis/ch0803-f2.htm   (141 words)

  
 Monitoring of nonlinear respiratory elastance using a multiple linear regression analysis -- Muramatsu et al. 17 (6): ...
A fundamental assumption of the SCM is that elastance
for elastance in a model 3, 13, 24, 25.
A comprehensive equation for the pulmonary pressure-volume curve.
erj.ersjournals.com /cgi/content/full/17/6/1158   (3407 words)

  
 Retinoic acid reverses the airway hyperresponsiveness but not the parenchymal defect that is associated with vitamin A ...
The mean concentrations (mg/ml) of aerosolized methacholine that produced a 20% increase in resistance (A) or a 2-fold increase in elastance (B) relative to aerosolized PBS were calculated using linear regression analysis of the data obtained from the studies shown in Fig.
Elastance is influenced by both alveolar and airway parameters.
elastance are associated with an increase in methacholine responsiveness.
ajplung.physiology.org /cgi/content/full/286/2/L437   (5335 words)

  
 BioMedical Engineering OnLine | Full text | Passive and active ventricular elastances of the left ventricle   (Site not responding. Last check: 2007-09-10)
The concept of compliance or elastance was first employed for blood vessels [3], by relating incremental cross-section area (or volume) and transmural pressure.
Later, the concept of a continuously varying compliance or elastance was adopted by a number of investigators with diverse variations [2,6,7].
The variations of model-derived nonlinear passive and active elastances for the subject HEL are shown in Figure 7.
www.biomedical-engineering-online.com /content/4/1/10   (3933 words)

  
 Role of rib cage elastance in the coupling between the abdominal muscles and the lung -- Cappello and De Troyer 97 (1): ...
elastance was increased by clamping the ribs and the sternum.
that the elastance of the rib cage was increased by a factor
with a twofold increase in rib cage elastance, the increase
jap.physiology.org /cgi/content/full/97/1/85   (3365 words)

  
 Method and apparatus for controlling an artificial respirator - Patent 4986268
Method according to claim 21 wherein the data representing metabolic rate ratio, lung elastance factor, air viscosity factor in the lung and barometric pressure is provided to the first means by monitors coupled to measure the same.
Lung elastance, air viscosity factor in the lungs and barometric pressure may be measured prior to operation of the device and supplied to the controller 12 through the reserved A/D channels or be stored in the software.
Values representing lung elastance factor, air viscosity factor in the lung and barometric pressure are read from the input ports or from the memory (if stored in the software) as shown at 206.
www.freepatentsonline.com /4986268.html   (6715 words)

  
 Introduction   (Site not responding. Last check: 2007-09-10)
Ventricular elastance was taken to be a monotonically increasing function of ventricular volume in order to include Starling's law: greater work done for larger end-diastolic volume.
Both groups of investigators found compliance or elastance values that were positive, negative, zero or infinite during a single cardiac cycle.
The time-varying elastance model assumes that all biochemical energy is stored in the elastance term.
shakti.trincoll.edu /~palladin/papers/embs98/node1.html   (661 words)

  
 Paper 17   (Site not responding. Last check: 2007-09-10)
Volume shifts are avoided by standardizing body posture (sitting) and, when it is likely that shifts will occur, for instance when the breathing pattern is voluntarily modified or bronchoconstriction or dilation are induced, by completing the measurements by a determination of absolute lung volume.
For the determination of pulmonary elastance and resistance, this is achieved by referring lung volumes to total lung capacity (TLC), and for airway resistance (body plethysmography) by measuring separately thoracic gas volume (TGV).
A change in elastance or resistance does not indicate whether the cause of the alteration is organic or functional and, as far as the resistance is concerned, whether it is occurring in the central or in the peripheral airways.
www.ohiou.edu /isarp/conf_03/paper_17.htm   (3100 words)

  
 Monitoring of nonlinear respiratory elastance using a multiple linear regression analysis -- Muramatsu et al. 17 (6): ...
Monitoring of nonlinear respiratory elastance using a multiple linear regression analysis -- Muramatsu et al.
Monitoring of nonlinear respiratory elastance using a multiple linear regression analysis
Keywords: elastance curve, multiple regression analysis, pressure/volume curve, respiratory mechanics, respiratory physiology
erj.ersjournals.com /cgi/content/abstract/17/6/1158   (236 words)

  
 APStracts 5:0298A, 1998.   (Site not responding. Last check: 2007-09-10)
We compared four algorithms using least-squares regression for determining pulmonary resistance and dynamic elastance in subjects with emphysema, normals and asthmatics before and after bronchoconstriction.
The four methods evaluated include: 1.) a single resistance and elastance 2.) separate resistances and elastances for each half breath 3.) separate inspiratory and expiratory resistances with a single elastance 4.) separate inspiratory and expiratory resistances, an expiratory volume interaction term and a single elastance.
In subjects who are flow limited, method 2 gives a higher inspiratory resistance than would be computed by assuming the elastic pressure volume curve passes through the zero flow points.
www.uth.tmc.edu /apstracts/1998/jap/July/298A.html   (246 words)

  
 Electrical elastance - Wikipedia, the free encyclopedia
Electrical inductor-capacitor-resistor circuits follow differential equations that can be interpreted as representing mass-spring-damper systems.
If voltage is taken to be force and current velocity, elastance corresponds to the elastic constant of a spring.
This page was last modified 16:12, 22 May 2006.
en.wikipedia.org /wiki/Electrical_elastance   (78 words)

  
 Rectal tone, distensibility, and perception: reproducibility and response to different distensions -- Hammer et al. 274 ...
Elastance of the rectum in response to volume-controlled distension was calculated by linear regression starting at a distension
Intraindividual day-to-day variabilities of rectal tone, elastance, and sensory thresholds were assessed for each of the five
slopes or the intercepts of the elastance curves.
ajpgi.physiology.org /cgi/content/full/274/3/G584   (3747 words)

  
 [No title]
Use of maximal forced expiration to assess pulmonary health: maximal forced expiration can relate how well the lung is functioning by comparing lung volumes to predicted lung volumes.
Decreased elastance (increased resistance) will diminish elastic recoil and will therefore decrease maximal expiratory flow.
Spirometry in measurement of forced exhalation: spirometry measures the volume of gas exhaled, when used in the clinical setting, spirometry can help in the calculation of the following values after a full inhalation and subsequent full exhalation into the spirometer.
www.u.arizona.edu /~ajgulbis/MedLinks/Physiology/PhysiologyType/37.doc   (250 words)

  
 Dysfunctional Mechanical Coupling of Upper Airway Tissues in Sleep Apnea Syndrome -- SÉRIÈS et al. 159 ...
Elastance was significantly lower in snorers than in patients with SAHS.
The increase in tissue elastance observed in patients with SAHS could be related to histological differences in UA tissues,
elastance because this axis corresponds to the orientation of
ajrccm.atsjournals.org /cgi/content/full/159/5/1551   (3407 words)

  
 elastance - OneLook Dictionary Search
Tip: Click on the first link on a line below to go directly to a page where "elastance" is defined.
elastance : Encarta® World English Dictionary, North American Edition [home, info]
elastance : Dorland's Illustrated Medical Dictionary [home, info]
www.onelook.com /?w=elastance   (105 words)

  
 Baroreceptor Modeling   (Site not responding. Last check: 2007-09-10)
The model simulates ventricular contraction as a time-dependent change in the elastance of the left ventricle during systole.
The time point in systole in turn sets the ventricular elastance, which in turn determines the ventricular volume.
The chronofactor modifies the elastance so that ventricular pressure rises faster as heart rate increases.
www.shodor.org /MASTER/biomed/physio/baroweb/algorithm.html   (508 words)

  
 Critical Care | Full text | Immediate post-operative effects of tracheotomy on respiratory function during mechanical ...
Furthermore, the duration of the tracheotomy procedure was not correlated with the percentage changes in the respiratory mechanics and blood gases.
Calculating reactance is not meaningless, because although it reflects the elastance it is influenced by respiratory frequency, which in our measurements varied from 10 to 20 cycles/min.
Changes in respiratory mechanics immediately after surgical tracheotomy might be important, especially in cases with an already increased elastance (for example in acute respiratory distress syndrome).
ccforum.com /content/8/4/R243   (2937 words)

  
 Impact of Vascular Adaptation to Chronic Aortic Regurgitation on Left Ventricular Performance -- Devlin et al. 99 (8): ...   (Site not responding. Last check: 2007-09-10)
elastance, a relatively load-independent index of LV contractility.
Note that despite no significant further change in LV contractility from Group IIa to IIb, there was a significant decrease in total arterial elastance in Group IIa in comparison to Group I, with an increase in total arterial load on the LV in Group IIb.
Group IIb demonstrates a deterioration in left ventricular-arterial coupling because of an increase in total arterial elastance, thereby double loading the LV and causing a marked deterioration in LV performance indicated by the decrease in normalized LV work.
circ.ahajournals.org /cgi/content/full/99/8/1027   (4282 words)

  
 Lung and chest wall mechanics in ventilated patients with end stage idiopathic pulmonary fibrosis -- Nava and Rubini 54 ...
The elastances and resistances of the respiratory system are significantly altered in ventilated patients with end stage idiopathic
Figure 2 shows the elastance of the respiratory system, lung, and chest wall during passive ventilation for each patient.
A significant increase in the elastance of the respiratory system was observed.
thorax.bmjjournals.com /cgi/content/full/54/5/390   (3378 words)

  
 Acute effects of bilateral lung volume reduction surgery on lung and chest wall properties CHEST - Find Articles   (Site not responding. Last check: 2007-09-10)
Study objectives: To characterize acute changes in the dynamic, passive mechanical properties of the lungs and chest wall, elastance (E) and resistance (R), caused by lung volume reduction surgery (LVRS).
Measurements and results: From measurements of airway and esophageal pressures and flow during mechanical ventilation throughout the physiologic range of breathing frequency (f) and tidal volume (VT), E and R of the total respiratory system (Ers and Rrs), lungs (EL and RL), and chest wall (Ecw and Rcw) immediately before and after LVRS were calculated.
In the present study, we studied immediate effects of bilateral LVRS on the mechanical properties (namely, dynamic elastance and resistance) of the lungs and chest walls of anesthetized/paralyzed patients still in the operating room.
www.findarticles.com /p/articles/mi_m0984/is_n1_v114/ai_21023636   (740 words)

  
 Systolic Elastance and Resistance in the Regulation of Cardiac Pumping Function in Early Streptozotocin-Diabetic Rats ...
Systolic Elastance and Resistance in the Regulation of Cardiac Pumping Function in Early Streptozotocin-Diabetic Rats -- Chang et al.
Systolic Elastance and Resistance in the Regulation of Cardiac Pumping Function in Early Streptozotocin-Diabetic Rats
Single-beat estimation of the ventricular pumping mechanics in terms of the systolic elastance and resistance.
www.ebmonline.org /cgi/content/full/227/4/251   (4018 words)

  
 Influence of baroreflex on volume elasticity of heart and aorta in the rabbit -- Wronski et al. 282 (3): 842 -- AJP - ...
ventricular endsystolic elastance is often taken as a measure
In addition, aortic VE during the diastole was generally higher in the cholesterol group.
Impact of arterial elastance as a measure of vascular load on left ventricular geometry in hypertension.
ajpregu.physiology.org /cgi/content/full/282/3/R842   (4482 words)

  
 Impairment of Lung and Chest Wall Mechanics in Patients with Acute Respiratory Distress Syndrome . Role of Abdominal ...
increase in coefficient a in Equation 1 (i.e., elastance at
to the increase in chest wall elastance related to abdominal distension.
wall elastance in patients with ARDS (3, 4, 19, 20).
ajrccm.atsjournals.org /cgi/content/full/156/4/1082   (5672 words)

  
 SCIREQ Measurements
Quasi-static elastance reflects the static elastic recoil pressure of the lungs at a given lung volume.
» Quasi-static Elastance is the inverse of the Quasi-static Compliance (Est = 1/Cst).
» For measurements of the dymamic elastance at and around breathing frequency, refer to E.
www.scireq.com /science/measurements/Est.html   (66 words)

  
 Publication Abstracts- Aerospace Medical Association
Cardiac output and mean arterial pressure were maintained throughout the simulation process by adjusting heart rate.
Results of the simulation showed that as arterial elastance decreased from its initially estimated (physiologic) value, external work increased slightly and as elastance increased, external work decreased.
In particular, we found that the arterial elastance was set at a point near that which would produce maximal external work.
www.asma.org /journal/abstracts/v72n1/v72n1p1.html   (314 words)

  
 SCIREQ Measurements
Elastance (E) Dynamic elastance captures the elastic rigidity of the lungs.
» Elastance is the inverse of the Compliance (E = 1/C).
» Dynamic elastance reflects the mechanical properties of the lungs for normal respiratory rates.
www.scireq.com /science/measurements/?m=E   (56 words)

  
 Role of rib cage elastance in the coupling between the abdominal muscles and the lung -- Cappello and De Troyer 97 (1): ...   (Site not responding. Last check: 2007-09-10)
Role of rib cage elastance in the coupling between the abdominal muscles and the lung -- Cappello and De Troyer 97 (1): 85 -- Journal of Applied Physiology (via CobWeb/3.1 planetlab2.isi.jhu.edu)
Articles by Cappello, M. Articles by De Troyer, A. Role of rib cage elastance in the coupling between the abdominal muscles and the lung
of rib cage elastance and Pab on the lung-deflating action of
www.jap.org.cob-web.org:8888 /cgi/content/abstract/97/1/85   (355 words)

  
 Determination of resonance frequency of the respiratory system in respiratory distress syndrome -- Lee et al. 80 (3): ...
Figure 1 Diagram of phase relation between driving signal and three components of impedance, resistance, elastance, and inertia.
The driving signal, which represents the changes in the piston position, is 90 degrees out of phase with flow.
The forced oscillatory method for measuring respiratory resistance was first introduced by DuBois and co-workers in 1955.
fn.bmjjournals.com /cgi/content/full/80/3/F198   (2371 words)

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