The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Shafique H. Keshavjee - One of the best experts on this subject based on the ideXlab platform.
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Simultaneous single-Lung transplantation and Lung Volume reduction
The Annals of thoracic surgery, 1997Co-Authors: Thomas R.j. Todd, Jean Perron, Timothy Winton, Shafique H. KeshavjeeAbstract:We report our experience with 2 cases of simultaneous single-Lung transplantation and Lung Volume reduction for emphysema. The Lung Volume reduction was undertaken electively in an attempt to improve overall Lung function above that to be expected from single-Lung transplantation alone. There were no postoperative problems related to the addition of Lung Volume reduction. The pulmonary function at 3 months was greater than that seen in a retrospective group of bilateral Lung transplants previously reported from our institution.
David P. White - One of the best experts on this subject based on the ideXlab platform.
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The influence of end-expiratory Lung Volume on measurements of pharyngeal collapsibility.
Journal of applied physiology (Bethesda Md. : 1985), 2009Co-Authors: Robert L. Owens, Atul Malhotra, David P. White, Danny J. Eckert, Amy S. JordanAbstract:Changes in end-expiratory Lung Volume (EELV) affect upper airway stability. The passive pharyngeal critical pressure (Pcrit), a measure of upper airway collapsibility, is determined using airway pressure drops. The EELV change during these drops has not been quantified and may differ between obese obstructive sleep apnea (OSA) patients and controls. Continuous positive airway pressure (CPAP)-treated OSA patients and controls were instrumented with an epiglottic catheter, magnetometers (to measure change in EELV), and a nasal mask/pneumotachograph. Subjects slept supine in a head-out plastic chamber in which the extrathoracic pressure could be lowered (to raise EELV) while on nasal CPAP. The magnitude of EELV change during Pcrit measurement (sudden reductions of CPAP for 3-5 breaths each minute) was assessed at baseline and with EELV increased approximately 500 ml. Fifteen OSA patients and 7 controls were studied. EELV change during Pcrit measurement was rapid and pressure dependent, but similar in OSA and control subjects (74 +/- 36 and 59 +/- 24 ml/cmH(2)O respectively, P = 0.33). Increased Lung Volume (mean +521 ml) decreased Pcrit by a similar amount in OSA and control subjects (-3.1 +/- 1.7 vs. -3.9 +/- 1.9 cmH(2)O, P = 0.31). Important Lung Volume changes occur during passive Pcrit measurement. However, on average, there is no difference in Lung Volume change for a given CPAP change between obese OSA subjects and controls. Changes in Lung Volume alter Pcrit substantially. This work supports a role for Lung Volume in the pathogenesis of OSA, and Lung Volume changes should be a consideration during assessment of pharyngeal mechanics.
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Effect of increased Lung Volume on sleep disordered breathing in patients with sleep apnoea
Thorax, 2006Co-Authors: Raphael Heinzer, Michael L. Stanchina, Atul Malhotra, Amy S. Jordan, Sanjay R. Patel, Andrew Wellman, Karen Schory, Louise Dover, David P. WhiteAbstract:Background: Previous studies have shown that changes in Lung Volume influence upper airway size and resistance, particularly in patients with obstructive sleep apnoea (OSA), and that continuous positive airway pressure (CPAP) requirements decrease when the Lung Volume is increased. We sought to determine the effect of a constant Lung Volume increase on sleep disordered breathing during non-REM sleep. Methods: Twelve subjects with OSA were studied during non-REM sleep in a rigid head-out shell equipped with a positive/negative pressure attachment for manipulation of extrathoracic pressure. The increase in Lung Volume due to CPAP (at a therapeutic level) was determined with four magnetometer coils placed on the chest wall and abdomen. CPAP was then stopped and the subjects were studied for 1 hour in three conditions (in random order): (1) no treatment (baseline); (2) at “CPAP Lung Volume”, with the increased Lung Volume being reproduced by negative extrathoracic pressure alone (Lung Volume 1, LV1); and (3) 500 ml above the CPAP Lung Volume(Lung Volume 2, LV2). Results: The mean (SE) apnoea/hypopnoea index (AHI) for baseline, LV1, and LV2, respectively, was 62.3 (10.2), 37.2 (5.0), and 31.2 (6.7) events per hour (p = 0.009); the 3% oxygen desaturation index was 43.0 (10.1), 16.1 (5.4), and 12.3 (5.3) events per hour (p = 0.002); and the mean oxygen saturation was 95.4 (0.3)%, 96.0 (0.2)%, 96.3 (0.3)%, respectively (p = 0.001). Conclusion: An increase in Lung Volume causes a substantial decrease in sleep disordered breathing in patients with OSA during non-REM sleep.
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Lung Volume and continuous positive airway pressure requirements in obstructive sleep apnea
American Journal of Respiratory and Critical Care Medicine, 2005Co-Authors: Raphael Heinzer, Michael L. Stanchina, Atul Malhotra, Amy S. Jordan, Sanjay R. Patel, Karen Schory, Robert B Fogel, David P. WhiteAbstract:Previous studies have demonstrated that Lung Volume during wakefulness influences upper airway size and resistance, particularly in patients with sleep apnea. We sought to determine the influence of Lung Volume on the level of continuous positive airway pressure (CPAP) required to prevent flow limitation during non-REM sleep in subjects with sleep apnea. Seventeen subjects (apnea–hypopnea index, 42.6 ± 6.2 [SEM]) were studied during stable non-REM sleep in a rigid head-out shell equipped with a positive/negative pressure attachment for manipulation of extrathoracic pressure. An epiglottic pressure catheter plus a mask/pneumotachometer were used to assess flow limitation. When Lung Volume was increased by 1,035 ± 22 ml, the CPAP level could be decreased from 11.9 ± 0.7 to 4.8 ± 0.7 cm H2O (p < 0.001) without flow limitation. The decreased CPAP at the same negative extrathoracic pressure yielded a final Lung Volume increase of 421 ± 36 ml above the initial value. Conversely, when Lung Volume was reduced by ...
Gerard J. Criner - One of the best experts on this subject based on the ideXlab platform.
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Lung Volume reduction surgery or bronchoscopic Lung Volume reduction: is there an algorithm for allocation?
Journal of Thoracic Disease, 2018Co-Authors: Matthew Gordon, Sean Duffy, Gerard J. CrinerAbstract:Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in the world with the annual number of deaths increasing every year. Alterations in chest wall mechanics, respiratory muscle mechanics, and impaired cardiac function that result from increased air-trapping are well known sequelae of COPD and contribute to increased morbidity and mortality. A reduction in hyperinflation can improve cardiopulmonary function. In selected patients with COPD and an emphysema phenotype, Lung Volume reduction surgery (LVRS) has demonstrated improvements in symptom burden and mortality. Minimally invasive bronchoscopic techniques that reduce end-expiratory Lung Volume have shown improvements in Lung function, dyspnea and quality of life. In this review, we review selection criteria, risks, and benefits of surgical and bronchoscopic Lung Volume reduction (BLVR). Recommendations are provided to guide treatment decisions based on the current literature.
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Alternatives to Lung transplantation: Lung Volume reduction for COPD.
Clinics in chest medicine, 2011Co-Authors: Gerard J. CrinerAbstract:Emphysema is disabling and progressive and hallmarked by decreased exercise tolerance and impaired quality of life. Surgical interventions that reduce Lung Volume have been the focus of multiple interventions for decades; however, until recently, limited evidence has documented their effectiveness. Lung Volume reduction surgery (LVRS) underwent rigorous study in the National Emphysema Treatment Trial (NETT), which demonstrated its short-term and long-term effectiveness, associated morbidity and mortality, and the essential factors that predict LVRS success or failure. This article summarizes the major results of the NETT and briefly reviews newer bronchoscopic Lung Volume reduction techniques that show promise as alternative treatments for select patients with COPD undergoing consideration for Lung transplantation.
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Lung Volume reduction surgery and Lung Volume reduction in advanced emphysema: who and why?
Seminars in respiratory and critical care medicine, 2010Co-Authors: Gerard J. Criner, A. James MamaryAbstract:Emphysema is a disabling and progressive disease that is hallmarked by decreased exercise tolerance and impaired quality of life. Hyperinflation is the sentinel physiological characteristic of emphysema that has been shown to be responsible for exercise intolerance, dyspnea, impaired quality of life, and mortality. Surgical interventions that reduce Lung Volume have been the focus of multiple proposed interventions over the past century; however, evidence documenting their effectiveness has been lacking. Recently, Lung Volume reduction surgery (LVRS) has undergone rigorous study in the National Emphysema Treatment Trial (NETT) that documented its short and long-term effectiveness, associated morbidity and mortality, and essential characteristics that predict success or failure. Additional recent investigation has examined the use of less invasive techniques, predominantly bronchoscopic techniques that reduce Lung Volume without open thoracotomy. This article summarizes the major results of the NETT and briefly reviews some preliminary results of studies examining new techniques of bronchoscopic Lung Volume reduction.
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Lung Volume reduction surgery and bronchoscopic Lung Volume reduction in severe emphysema
Respiratory Medicine: COPD Update, 2008Co-Authors: A. James Mamary, Gerard J. CrinerAbstract:Abstract Lung Volume reduction surgery (LVRS) improves the fit of severely hyperinflated emphysematous Lungs to the surrounding chest cavity and thereby improves respiratory mechanics and expiratory airflow. LVRS is a potent and life extending therapy for some patients with severe emphysema and has a low associated operative mortality. The national emphysema treatment trial (NETT) identified characteristics of patients for whom LVRS improves survival, function and health-related quality of life and characteristics of patients who should not have surgery. Patients with upper-lobe predominant distribution of emphysema on high-resolution computed tomogram are most likely to benefit from LVRS vs. optimal medical therapy and rehabilitation. At long-term follow-up, the survival and functional benefits derived from LVRS are durable. In efforts to make Lung Volume reduction safer and more broadly accessible physician-scientists have developed bronchoscopic Lung Volume reduction (BLVR) procedures. Early clinical trials of BLVR performed with endobronchial valves (EVB) and sclerosant biogels demonstrate their safety. The ability of BLVR EBV techniques to produce desired atelectasis and Lung Volume loss is likely limited in those patients with collateral ventilation, incomplete fissures and those unable to achieve complete lobar exclusion. Results from a phase III BLVR EBV trial are in analysis.
Thomas R.j. Todd - One of the best experts on this subject based on the ideXlab platform.
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Simultaneous single-Lung transplantation and Lung Volume reduction
The Annals of thoracic surgery, 1997Co-Authors: Thomas R.j. Todd, Jean Perron, Timothy Winton, Shafique H. KeshavjeeAbstract:We report our experience with 2 cases of simultaneous single-Lung transplantation and Lung Volume reduction for emphysema. The Lung Volume reduction was undertaken electively in an attempt to improve overall Lung function above that to be expected from single-Lung transplantation alone. There were no postoperative problems related to the addition of Lung Volume reduction. The pulmonary function at 3 months was greater than that seen in a retrospective group of bilateral Lung transplants previously reported from our institution.
Kai Rehder - One of the best experts on this subject based on the ideXlab platform.
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Halothane changes the relationships between Lung resistances and Lung Volume.
Anesthesiology, 1992Co-Authors: Michael J. Joyner, David O. Warner, Kai RehderAbstract:The authors hypothesized that relaxation of airway smooth muscle by halothane lessens the dependence of airway resistance on Lung Volume, and that halothane alters the relationship between pulmonary resistance and Lung Volume by changing both the airway and tissue components of pulmonary resistance. The relationship among airway resistance, tissue resistance, and Lung Volume was examined in mongrel dogs before and during the administration of halothane, both in airways with reduced smooth muscle tone (after vagotomy) and during moderate increases in smooth muscle tone caused by vagus nerve stimulation (VNS). Resistance were measured at several levels of positive end-expiratory pressure (PEEP, 4-15 cmH2O) using an alveolar capsule technique. Before halothane administration, airway resistance increased at low PEEP; VNS accentuated this increase. Tissue resistance increased at low PEEP only during VNS. Halothane had no significant effect on any resistance before VNS. During VNS, halothane markedly blunted increases in airway resistance and tissue resistance as PEEP decreased. The authors conclude that during stimulation of airway smooth muscle in dogs, halothane attenuates increases in airway resistance and tissue resistance with reductions in Lung Volume in dogs. Thus, moderate changes in Lung Volume have little effect on these resistances during halothane anesthesia under these conditions.
