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dead space fraction

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https://www.readbyqxmd.com/read/29341986/pulmonary-dead-space-fraction-and-extubation-success-in-children-after-cardiac-surgery
#1
Renee L Devor, Paul Kang, Chasity Wellnitz, John J Nigro, Daniel A Velez, Brigham C Willis
OBJECTIVES: 1) Determine the correlation between pulmonary dead space fraction and extubation success in postoperative pediatric cardiac patients; and 2) document the natural history of pulmonary dead space fractions, dynamic compliance, and airway resistance during the first 72 hours postoperatively in postoperative pediatric cardiac patients. DESIGN: A retrospective chart review. SETTING: Cardiac ICU in a quaternary care free-standing children's hospital...
January 16, 2018: Pediatric Critical Care Medicine
https://www.readbyqxmd.com/read/29283360/the-influence-of-dilution-on-the-offline-measurement-of-exhaled-nitric-oxide
#2
Victoria MacBean, Dharmika Pooranampillai, Catherine Howard, Alan Charles Lunt, Anne Greenough
Measurement of fractional exhaled nitric oxide (FeNO) is used to determine the presence and severity of eosinophilic airway inflammation in asthma and other wheezing illnesses. The gold standard of online measurement during a single prolonged exhalation is not suitable for use in young children. The international guidelines for offline measurements recommend collection of exhaled gas in an appropriate reservoir for later analysis in young children. The apparatus required for gas collection, however, creates dead space within the system, which may result in sample dilution and hence inaccuracy...
December 28, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/29261402/oral-versus-nasal-high-flow-bronchodilator-inhalation-in-chronic-obstructive-pulmonary-disease
#3
Jens Bräunlich, Hubert Wirtz
BACKGROUND: Nasal high flow (NHF) alters breathing patterns, stabilizes fraction of inspired oxygen (FiO2) during respiratory distress, helps to keep up hemostasis in the airways, and washes out the upper airways. Particularly the support of inspiratory flow and decrease in functional dead space are interesting mechanisms of action with regard to aerosol delivery. Several laboratory investigations have studied aerosol delivery via the nasal route by using NHF, whereas clinical benefits are poorly evaluated...
December 20, 2017: Journal of Aerosol Medicine and Pulmonary Drug Delivery
https://www.readbyqxmd.com/read/29246713/determination-of-physiological-dead-space-in-anaesthetized-horses-a-method-comparison-study
#4
Zuzana Drábková, Johannes P Schramel, Radovan Kabeš
OBJECTIVE: To compare two methods of Bohr-Enghoff physiological dead space to tidal volume ratio (VD/VTBohr-Enghoff) determination using a mixing chamber and an E-CAiOVX metabolic monitor. STUDY DESIGN: Prospective, clinical, method-comparison study. ANIMALS: Twenty horses anaesthetized for elective orthopaedic procedures. METHODS: Horses were anaesthetized with isoflurane in oxygen and the lungs were mechanically ventilated (VT 15±2 mL kg-1)...
April 18, 2017: Veterinary Anaesthesia and Analgesia
https://www.readbyqxmd.com/read/29189669/measurement-of-dead-space-fraction-upon-icu-admission-predicts-length-of-stay-and-clinical-outcomes-following-bidirectional-cavopulmonary-anastomosis
#5
Claire L Cigarroa, Sarah J van den Bosch, Xiaoqi Tang, Kimberlee Gauvreau, Christopher W Baird, James A DiNardo, John Nagi Kheir
OBJECTIVES: Increased alveolar dead space fraction has been associated with prolonged mechanical ventilation and increased mortality in pediatric patients with respiratory failure. The association of alveolar dead space fraction with clinical outcomes in patients undergoing bidirectional cavopulmonary anastomosis for single ventricle congenital heart disease has not been reported. We describe an association of alveolar dead space fraction with postoperative outcomes in patients undergoing bidirectional cavopulmonary anastomosis...
January 2018: Pediatric Critical Care Medicine
https://www.readbyqxmd.com/read/29052522/predictors-of-diffuse-alveolar-damage-in-patients-with-acute-respiratory-distress-syndrome-a-retrospective-analysis-of-clinical-autopsies
#6
Arnaud W Thille, Oscar Peñuelas, José A Lorente, Pilar Fernández-Segoviano, José-Maria Rodriguez, José-Antonio Aramburu, Julian Panizo, Andres Esteban, Fernando Frutos-Vivar
BACKGROUND: Although diffuse alveolar damage (DAD) is considered the typical histological pattern of acute respiratory distress syndrome (ARDS), only half of patients exhibit this morphological hallmark. Patients with DAD may have higher mortality than those without DAD. Therefore, we aimed to identify the factors associated with DAD in patients with ARDS. METHODS: We analyzed autopsy samples of 356 patients who had ARDS at the time of death. DAD was assessed by two pathologists, and ARDS criteria were evaluated by two intensivists...
October 20, 2017: Critical Care: the Official Journal of the Critical Care Forum
https://www.readbyqxmd.com/read/28990307/physiological-dead-space-and-arterial-carbon-dioxide-contributions-to-exercise-ventilatory-inefficiency-in-patients-with-reduced-or-preserved-ejection-fraction-heart-failure
#7
Erik H Van Iterson, Bruce D Johnson, Barry A Borlaug, Thomas P Olson
AIMS: Patients with heart failure (HF) with reduced (HFrEF) or preserved (HFpEF) ejection fraction demonstrate an increased ventilatory equivalent for carbon dioxide (V̇E /V̇CO2 ) slope. The physiological correlates of the V̇E /V̇CO2 slope remain unclear in the two HF phenotypes. We hypothesized that changes in the physiological dead space to tidal volume ratio (VD /VT ) and arterial CO2 tension (PaCO2 ) differentially contribute to the V̇E /V̇CO2 slope in HFrEF vs. HFpEF. METHODS AND RESULTS: Adults with HFrEF (n = 32) and HFpEF (n = 27) [mean ± standard deviation (SD) left ventricular ejection fraction: 22 ± 7% and 61 ± 9%, respectively; mean ± SD body mass index: 28 ± 4 kg/m2 and 33 ± 6 kg/m2 , respectively; P < 0...
October 8, 2017: European Journal of Heart Failure
https://www.readbyqxmd.com/read/28828372/high-flow-nasal-oxygen-therapy-and-noninvasive-ventilation-in-the-management-of-acute-hypoxemic-respiratory-failure
#8
REVIEW
Jean-Pierre Frat, Rémi Coudroy, Nicolas Marjanovic, Arnaud W Thille
High-flow nasal cannula (HFNC) oxygen therapy is a recent technique delivering a high flow of heated and humidified gas. HFNC is simpler to use and apply than noninvasive ventilation (NIV) and appears to be a good alternative treatment for hypoxemic acute respiratory failure (ARF). HFNC is better tolerated than NIV, delivers high fraction of inspired oxygen (FiO2), generates a low level of positive pressure and provides washout of dead space in the upper airways, thereby improving mechanical pulmonary properties and unloading inspiratory muscles during ARF...
July 2017: Annals of Translational Medicine
https://www.readbyqxmd.com/read/28794144/nasal-high-flow-therapy-a-novel-treatment-rather-than-a-more-expensive-oxygen-device
#9
REVIEW
Eleni Ischaki, Ioannis Pantazopoulos, Spyros Zakynthinos
Nasal high flow is a promising novel oxygen delivery device, whose mechanisms of action offer some beneficial effects over conventional oxygen systems. The administration of a high flow of heated and humidified gas mixture promotes higher and more stable inspiratory oxygen fraction values, decreases anatomical dead space and generates a positive airway pressure that can reduce the work of breathing and enhance patient comfort and tolerance. Nasal high flow has been used as a prophylactic tool or as a treatment device mostly in patients with acute hypoxaemic respiratory failure, with the majority of studies showing positive results...
September 30, 2017: European Respiratory Review: An Official Journal of the European Respiratory Society
https://www.readbyqxmd.com/read/28756120/comparison-of-two-strategies-for-ex-vivo-lung-perfusion
#10
Tobias Nilsson, Jan F Gielis, Alexis Slama, Christoffer Hansson, Andreas Wallinder, Sven-Erik Ricksten, Göran Dellgren
BACKGROUND: Two clinically used strategies for ex vivo lung perfusion (EVLP) were compared in a porcine model with respect to lung function, metabolism, inflammatory response, oxidative stress, and cell viability. METHODS: Porcine lungs (n = 20) were preserved, harvested, and kept cooled for 2 hours. After randomization, EVLP was performed using a cellular perfusate and open left atrium (COA group) or an acellular perfusate and a closed left atrium (ACA group). Oxygenation (partial pressure of arterial oxygen/fraction of inspired oxygen), compliance, dead space, weight, and perfusate oncotic pressure were registered before and after a 4-hour period of reconditioning...
July 8, 2017: Journal of Heart and Lung Transplantation
https://www.readbyqxmd.com/read/28666570/dead-space-ventilation-is-linked-to-exercise-capacity-and-survival-in-distal-chronic-thromboembolic-pulmonary-hypertension
#11
Laurent Godinas, Caroline Sattler, Edmund M Lau, Xavier Jaïs, Yu Taniguchi, Mitja Jevnikar, Jason Weatherald, Olivier Sitbon, Laurent Savale, David Montani, Gérald Simonneau, Marc Humbert, Pierantonio Laveneziana, Gilles Garcia
BACKGROUND: Cardiopulmonary exercise testing (CPET) is frequently used for the evaluation of patients with pulmonary hypertension (PH). Non-operable distal chronic thromboembolic pulmonary hypertension (CTEPH) represents a unique subgroup of PH where microvascular disease resembling pulmonary arterial hypertension (PAH) may predominate and efficacious medical therapy is now available. However, little is known regarding the detailed CPET profile of patients with distal CTEPH, and whether ventilation and gas exchange responses are different from PAH...
November 2017: Journal of Heart and Lung Transplantation
https://www.readbyqxmd.com/read/28665692/excess-ventilation-in-chronic-obstructive-pulmonary-disease-heart-failure-overlap-implications-for-dyspnea-and-exercise-intolerance
#12
Alcides Rocha, Flavio F Arbex, Priscilla A Sperandio, Aline Souza, Ligia Biazzim, Frederico Mancuso, Danilo C Berton, Bruno Hochhegger, Maria Clara N Alencar, Luiz E Nery, Denis E O'Donnell, J Alberto Neder
RATIONALE: An increased ventilatory response to exertional metabolic demand (high [Formula: see text]e/[Formula: see text]co2 relationship) is a common finding in patients with coexistent chronic obstructive pulmonary disease and heart failure. OBJECTIVES: We aimed to determine the mechanisms underlying high [Formula: see text]e/[Formula: see text]co2 and its impact on operating lung volumes, dyspnea, and exercise tolerance in these patients. METHODS: Twenty-two ex-smokers with combined chronic obstructive pulmonary disease and heart failure with reduced left ventricular ejection fraction undertook, after careful treatment optimization, a progressive cycle exercise test with capillary (c) blood gas collection...
November 15, 2017: American Journal of Respiratory and Critical Care Medicine
https://www.readbyqxmd.com/read/28611227/lung-injury-etiology-and-other-factors-influencing-the-relationship-between-dead-space-fraction-and-mortality-in-ards
#13
Richard H Kallet, Hanjing Zhuo, Kelly Ho, Michael S Lipnick, Antonio Gomez, Michael A Matthay
BACKGROUND: In ARDS, elevated pulmonary dead-space fraction (VD/VT) is a particularly strong indicator of mortality risk. Whether the magnitude of VD/VT is modified by the underlying etiology of ARDS and whether this influences the strength of its association with mortality remains unknown. We sought to elucidate the impact of ARDS etiology on VD/VT and also to determine whether ARDS severity, as classified by the Berlin definition, has correspondence with changes in VD/VT. METHODS: This single-center, retrospective, observational study (2010-2016) measured VD/VT in 685 subjects with ARDS as part of clinical management with lung-protective ventilation...
October 2017: Respiratory Care
https://www.readbyqxmd.com/read/28599888/cardiopulmonary-effects-of-pleural-insufflation-with-co2-during-two-lung-ventilation-in-dorsally-recumbent-anesthetized-horses
#14
Kaylee S Bohaychuk-Preuss, M Valentina Carrozzo, Tanya Duke-Novakovski
OBJECTIVE: To record the cardiopulmonary effects of pleural CO2 positive pressure insufflation in anesthetized horses. STUDY DESIGN: Prospective study. ANIMALS: Seven horses (mean ± standard deviation, 530.9 ± 68.1 kg) undergoing terminal surgery. METHODS: Horses were sedated with xylazine. Anesthesia was induced with ketamine-propofol and maintained with isoflurane, positive pressure ventilation, detomidine infusion, and butorphanol with the horses in dorsal recumbency...
January 10, 2017: Veterinary Anaesthesia and Analgesia
https://www.readbyqxmd.com/read/28596273/novel-analysis-of-4dct-imaging-quantifies-progressive-increases-in-anatomic-dead-space-during-mechanical-ventilation-in-mice
#15
Elizabeth H Kim, Melissa Preissner, Richard P Carnibella, Chaminda R Samarage, Ellen Bennett, Marcio A Diniz, Andreas Fouras, Graeme R Zosky, Heather D Jones
Increased dead space is an important prognostic marker in early acute respiratory distress syndrome (ARDS) that correlates with mortality. The cause of increased dead space in ARDS has largely been attributed to increased alveolar dead space due to ventilation/perfusion mismatching and shunt. We sought to determine whether anatomic dead space also increases in response to mechanical ventilation. Mice received intratracheal lipopolysaccharide (LPS) or saline and mechanical ventilation (MV). Four-dimensional computed tomography (4DCT) scans were performed at onset of MV and after 5 h of MV...
September 1, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28578708/effects-of-neurally-adjusted-ventilatory-assist-on-air-distribution-and-dead-space-in-patients-with-acute-exacerbation-of-chronic-obstructive-pulmonary-disease
#16
Qin Sun, Ling Liu, Chun Pan, Zhanqi Zhao, Jingyuan Xu, Airan Liu, Haibo Qiu
BACKGROUND: Neurally adjusted ventilatory assist (NAVA) could improve patient-ventilator interaction; its effects on ventilation distribution and dead space are still unknown. The aim of this study was to evaluate the effects of varying levels of assist during NAVA and pressure support ventilation (PSV) on ventilation distribution and dead space in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). METHODS: Fifteen mechanically ventilated patients with AECOPD were included in the study...
June 2, 2017: Critical Care: the Official Journal of the Critical Care Forum
https://www.readbyqxmd.com/read/28475040/model-based-estimation-of-respiratory-parameters-from-capnography-with-application-to-diagnosing-obstructive-lung-disease
#17
Abubakar Abid, Rebecca J Mieloszyk, George C Verghese, Baruch S Krauss, Thomas Heldt
OBJECTIVE: We use a single-alveolar-compartment model to describe the partial pressure of carbon dioxide in exhaled breath, as recorded in time-based capnography. Respiratory parameters are estimated using this model and then related to the clinical status of patients with obstructive lung disease. METHODS: Given appropriate assumptions, we derive an analytical solution of the model, describing the exhalation segment of the capnogram. This solution is parametrized by alveolar CO2 concentration, dead-space fraction, and the time constant associated with exhalation...
May 2, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28427718/improved-linear-quadratic-and-proportional-control-system-for-improved-liquid-level-system-regulation-in-a-coke-fractionation-tower
#18
Jili Tao, Qinru Fan, Longhua Ma
A new linear quadratic regulation (LQ) control plus a proportional (P) control system is proposed for the level regulation in an industrial coke fractionation tower. The process is first stabilized using a P controller and then a subsequent LQ controller is designed for the P control system. The P control system is modeled as a generalized first order plus dead time (FOPDT) process using step-response test and the LQ-P controller is designed through a new state space structure. Performance in terms of regulatory and servo issues were investigated...
April 17, 2017: ISA Transactions
https://www.readbyqxmd.com/read/28413511/application-of-dead-space-fraction-to-titrate-optimal-positive-end-expiratory-pressure-in-an-ards-swine-model
#19
Weishuai Bian, Wei Chen, Yangong Chao, Lan Wang, Liming Li, Jian Guan, Xuefeng Zang, Jie Zhen, Bo Sheng, Xi Zhu
This study aimed to apply the dead space fraction [ratio of dead space to tidal volume (VD/VT)] to titrate the optimal positive end-expiratory pressure (PEEP) in a swine model of acute respiratory distress syndrome (ARDS). Twelve swine models of ARDS were constructed. A lung recruitment maneuver was then conducted and the PEEP was set at 20 cm H2O. The PEEP was reduced by 2 cm H2O every 10 min until 0 cm H2O was reached, and VD/VT was measured after each decrement step. VD/VT was measured using single-breath analysis of CO2, and calculated from arterial CO2 partial pressure (PaCO2) and mixed expired CO2 (PeCO2) using the following formula: VD/VT = (PaCO2 - PeCO2)/PaCO2...
April 2017: Experimental and Therapeutic Medicine
https://www.readbyqxmd.com/read/28372575/implementing-a-bedside-assessment-of-respiratory-mechanics-in-patients-with-acute-respiratory-distress-syndrome
#20
Lu Chen, Guang-Qiang Chen, Kevin Shore, Orest Shklar, Concetta Martins, Brian Devenyi, Paul Lindsay, Heather McPhail, Ashley Lanys, Ibrahim Soliman, Mazin Tuma, Michael Kim, Kerri Porretta, Pamela Greco, Hilary Every, Chris Hayes, Andrew Baker, Jan O Friedrich, Laurent Brochard
BACKGROUND: Despite their potential interest for clinical management, measurements of respiratory mechanics in patients with acute respiratory distress syndrome (ARDS) are seldom performed in routine practice. We introduced a systematic assessment of respiratory mechanics in our clinical practice. After the first year of clinical use, we retrospectively assessed whether these measurements had any influence on clinical management and physiological parameters associated with clinical outcomes by comparing their value before and after performing the test...
April 4, 2017: Critical Care: the Official Journal of the Critical Care Forum
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