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Ventilation-perfusion mismatch

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https://www.readbyqxmd.com/read/30057872/imaging-of-acute-pulmonary-embolism-an-update
#1
REVIEW
Alastair J E Moore, Jason Wachsmann, Murthy R Chamarthy, Lloyd Panjikaran, Yuki Tanabe, Prabhakar Rajiah
Imaging plays an important role in the evaluation and management of acute pulmonary embolism (PE). Computed tomography (CT) pulmonary angiography (CTPA) is the current standard of care and provides accurate diagnosis with rapid turnaround time. CT also provides information on other potential causes of acute chest pain. With dual-energy CT, lung perfusion abnormalities can also be detected and quantified. Chest radiograph has limited utility, occasionally showing findings of PE or infarction, but is useful in evaluating other potential causes of chest pain...
June 2018: Cardiovascular Diagnosis and Therapy
https://www.readbyqxmd.com/read/30049524/effect-of-one-lung-ventilation-on-blood-sevoflurane-and-desflurane-concentrations
#2
Ebru Biricik, Feride Karacaer, Yasemin Güneş, Nebile Dağlıoğlu, Pınar Efeoğlu, Murat Ilgınel, Alper Avcı, Dilek Özcengiz
OBJECTIVE: To determine the blood sevoflurane and desflurane concentrations during one-lung ventilation (OLV). DESIGN: Randomized, single-blind study. SETTING: Single university hospital. PARTICIPANTS: The study comprised 24 patients, 35 to 70 years old who were scheduled for either a major abdominal surgery or thoracotomy. INTERVENTIONS: The patients were divided into the following 4 groups: sevoflurane two-lung ventilation (TLV), sevoflurane OLV, desflurane TLV, and desflurane OLV...
June 1, 2018: Journal of Cardiothoracic and Vascular Anesthesia
https://www.readbyqxmd.com/read/29945812/-pathophysiology-of-right-ventricular-hemodynamics
#3
REVIEW
D Chemla, E Berthelot, P Assayag, P Attal, P Hervé
The right ventricle (RV) plays a key role in the maintenance of an adequate cardiac output whatever the demand, and thus contributes to the optimization of the ventilation/perfusion ratio. The RV has a thin wall and it buffers the physiological increases in systemic venous return without causing a deleterious rise in right atrial pressure (RAP). The RV is coupled to the pulmonary circulation which is a low pressure, low resistance, high compliance system. In the healthy subject at rest, the contribution of the RV to right heart systolic function is surpassed by the contribution of both left ventricular contraction and the respiratory pump...
June 23, 2018: Revue des Maladies Respiratoires
https://www.readbyqxmd.com/read/29871009/-lung-scintigraphy
#4
Carl Schümichen, Matthias Schmidt, Thomas Krause
The S1 guideline for lung scintigraphy has been updated and extended in order to emphasize the advantages oft the method in detecting acute pulmonary embolism (PE) in the periphery oft the lung (subsegmental PE), in underlying subacute and chronic pulmonary disorders, as well as in detecting chronic LE (CTEPH). Method of choice is ventilation / perfusion (V/P) SPECT or V/P SPECT/CT with even higher specificity. Because of its high sensitivity, a threshold (V/P mismatch in at least one segment or two subsegments) is introduced to avoid overtreatment...
June 2018: Nuklearmedizin. Nuclear Medicine
https://www.readbyqxmd.com/read/29850168/non-intubated-anaesthetic-technique-in-open-bilobectomy-in-a-patient-with-severely-impaired-lung-function
#5
Zsolt Szabó, Tamás Tanczos, Gábor Lebak, Zsolt Molnár, József Furák
General anaesthesia has been the most commonly used method for almost all types of thoracic surgery. Recently, there has been a growing interest in non-intubated anaesthetic techniques. The rationale being, to prevent complications related to general anaesthesia and positive pressure ventilation such as barotrauma or ventilation-perfusion mismatch. We present a case with severely impaired forced expiration volume (26%), carbon monoxide diffusing capacity (26%) and VO2 max (13.9 mL/kg/min). According to current guidelines, this patient was suitable to undergo one-lung ventilation only with high risk of morbidity and mortality...
April 2018: Journal of Thoracic Disease
https://www.readbyqxmd.com/read/29846802/dual-energy-ct-dect-lung-perfusion-in-pulmonary-hypertension-concordance-rate-with-v-q-scintigraphy-in-diagnosing-chronic-thromboembolic-pulmonary-hypertension-cteph
#6
Matthieu Masy, Jessica Giordano, Grégory Petyt, Claude Hossein-Foucher, Alain Duhamel, Maeva Kyheng, Pascal De Groote, Marie Fertin, Nicolas Lamblin, Jean-François Bervar, Jacques Remy, Martine Remy-Jardin
OBJECTIVES: To evaluate the concordance between DECT perfusion and ventilation/perfusion (V/Q) scintigraphy in diagnosing chronic thromboembolic pulmonary hypertension (CTEPH). METHODS: Eighty patients underwent V/Q scintigraphy and DECT perfusion on a 2nd- and 3rd-generation dual-source CT system. The imaging criteria for diagnosing CTEPH relied on at least one segmental triangular perfusion defect on DECT perfusion studies and V/Q mismatch on scintigraphy examinations...
May 30, 2018: European Radiology
https://www.readbyqxmd.com/read/29846298/a-case-series-of-outcomes-in-isolated-subsegmental-pulmonary-embolism-on-ventilation-perfusion-imaging
#7
Amy Mallorie, Kenneth Chan, Stefanos Ioannidis, Matthew Stubbs, Shaunak Navalkissoor, Thomas Wagner
OBJECTIVES: The risk of recurrent venous thromboembolic disease and the management of patients with isolated subsegmental pulmonary embolism (SSPE) remain unclear. We sought to assess the long-term clinical outcome of patients with isolated SSPE demonstrated by isolated subsegmental mismatch found on ventilation/perfusion (V/Q) scans. PATIENTS AND METHODS: We performed a retrospective observational study of 1300 consecutive patients with suspected pulmonary embolism who underwent index V/Q single-photon emission computed tomography between 2012 and 2013...
July 2018: Nuclear Medicine Communications
https://www.readbyqxmd.com/read/29808762/cardiopulmonary-exercise-testing-reveals-subclinical-abnormalities-in-chronic-kidney-disease
#8
Danielle L Kirkman, Bryce J Muth, Joseph M Stock, Raymond R Townsend, David G Edwards
Background Reductions in exercise capacity associated with exercise intolerance augment cardiovascular disease risk and predict mortality in chronic kidney disease. This study utilized cardiopulmonary exercise testing to (a) investigate mechanisms of exercise intolerance; (b) unmask subclinical abnormalities that may precede cardiovascular disease in chronic kidney disease. Design The design of this study was cross-sectional. Methods Cardiopulmonary exercise testing was carried out in 31 Stage 3-4 chronic kidney disease patients (60 ± 11 years; estimated glomerular filtration rate 43 ± 13 ml/min/1...
January 1, 2018: European Journal of Preventive Cardiology
https://www.readbyqxmd.com/read/29775966/an-enigmatic-case-presentation-of-budd-chiari-syndrome-with-pulmonary-embolism-an-unusual-syndrome-with-an-uncommon-complication
#9
A M Al-Sharydah, A H Al-Abdulwahhab, H A Abu AlOla
INTRODUCTION: In patients with a hypercoagulable state, such as patients with pulmonary embolism and/or Budd-Chiari syndrome, the complications from multiple gene mutations are more numerous than those from a single mutation. The authors present a woman with no major prior medical history who presented with pulmonary embolism and Budd-Chiari syndrome; this enigmatic co-occurrence has never been solely reported without underlying aetiology in a patient without prior medical conditions...
2018: International Journal of Surgery Case Reports
https://www.readbyqxmd.com/read/29761310/characteristics-of-patients-with-a-relatively-greater-minimum-ve-vco-2-against-peak-vo-2-and-impaired-exercise-tolerance
#10
Taisuke Nakade, Hitoshi Adachi, Makoto Murata, Shigeru Oshima
PURPOSE: Cardiopulmonary exercise testing (CPX) is used to evaluate functional capacity and assess prognosis in cardiac patients. Ventilatory efficiency (VE/VCO2 ) reflects ventilation-perfusion mismatch; the minimum VE/VCO2 value (minVE/VCO2 ) is representative of pulmonary arterial blood flow in individuals without pulmonary disease. Usually, minVE/VCO2 has a strong relationship with the peak oxygen uptake (VO2 ), but dissociation can occur. Therefore, we investigated the relationship between minVE/VCO2 and predicted peak VO2 (peak VO2 %) and evaluated the parameters associated with a discrepancy between these two parameters...
May 14, 2018: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/29695441/pulmonary-ventilation-perfusion-mismatch-a-novel-hypothesis-for-how-diving-vertebrates-may-avoid-the-bends
#11
REVIEW
Daniel Garcia Párraga, Michael Moore, Andreas Fahlman
Hydrostatic lung compression in diving marine mammals, with collapsing alveoli blocking gas exchange at depth, has been the main theoretical basis for limiting N2 uptake and avoiding gas emboli (GE) as they ascend. However, studies of beached and bycaught cetaceans and sea turtles imply that air-breathing marine vertebrates may, under unusual circumstances, develop GE that result in decompression sickness (DCS) symptoms. Theoretical modelling of tissue and blood gas dynamics of breath-hold divers suggests that changes in perfusion and blood flow distribution may also play a significant role...
April 25, 2018: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/29680830/pulmonary-perfusion-using-intrabronchial-capnography-in-pulmonary-artery-stenosis
#12
Hiroki Nishine, Hiromi Muraoka, Takeo Inoue, Teruomi Miyazawa, Masamichi Mineshita
Stenting at the flow-limiting segment can improve the ventilation-perfusion ratio in patients with central airway stenosis. However, there is no quantitative examination for assessing the perfusion status during interventional bronchoscopy. Intrabronchial capnography can estimate regional gas exchange by measuring carbon dioxide concentration. We herein report a case of bilateral bronchial stenosis where stenting was able to improve ventilation-perfusion ratio using intrabronchial capnography. A 44-year-old man was admitted to our institution with orthopnea...
2018: Respiration; International Review of Thoracic Diseases
https://www.readbyqxmd.com/read/29678310/grossly-abnormal-ventilation-perfusion-spect-study-in-idiopathic-pulmonary-arterial-hypertension-without-thromboembolism
#13
Kenneth Chan, John G Coghlan, Margaret Hall, Jamanda Haddock, Alan Bates, Benjamin E Schreiber
Pulmonary hypertension is a serious condition with multiple underlying aetiologies which require different treatment strategies. We present a case of severe idiopathic pulmonary arterial hypertension in a 20-year-old patient with ongoing breathlessness. She was initially diagnosed with asthma and panic attacks in community care. As the symptoms became progressively worse, she was referred for pulmonary hypertension clinic assessment. Ventilation/perfusion single-photon emission computed tomography (V/Q SPECT) showed grossly abnormal perfusion defects which were mismatched to the ventilation scan, suggestive of chronic thromboembolic disease...
January 31, 2018: Heart, Lung & Circulation
https://www.readbyqxmd.com/read/29599604/review-article-update-on-current-and-emergent-data-on-hepatopulmonary-syndrome
#14
REVIEW
Stergios Soulaidopoulos, Evangelos Cholongitas, George Giannakoulas, Maria Vlachou, Ioannis Goulis
Hepatopulmonary syndrome (HPS) is a frequent pulmonary complication of end-stage liver disease, characterized by impaired arterial oxygenation induced by intrapulmonary vascular dilatation. Its prevalence ranges from 4% to 47% in patients with cirrhosis due to the different diagnostic criteria applied among different studies. Nitric oxide overproduction and angiogenesis seem to be the hallmarks of a complicated pathogenetic mechanism, leading to intrapulmonary shunting and ventilation-perfusion mismatch. A classification of HPS according to the severity of hypoxemia has been suggested...
March 28, 2018: World Journal of Gastroenterology: WJG
https://www.readbyqxmd.com/read/29579597/physiological-insights-of-exercise-hyperventilation-in-arterial-and-chronic-thromboembolic-pulmonary-hypertension
#15
Stefania Farina, Noemi Bruno, Cecilia Agalbato, Mauro Contini, Roberto Cassandro, Davide Elia, Sergio Harari, Piergiuseppe Agostoni
BACKGROUND: Pulmonary hypertension (PH) patients show, during exercise, an excessive increase in ventilation (VE ) compared to carbon dioxide output (VCO2 ), determining a high VE /VCO2 slope. There are several possible causes, including an elevated dead space ventilation (VD ), VE /perfusion (Q) mismatch and/or an enhanced peripheral or central chemoreceptor activity. We evaluated the causes of exercise hyperventilation in PH patients. METHODS: Eighteen group I and IV PH patients underwent cardiopulmonary exercise test with blood gas analysis at every minute...
May 15, 2018: International Journal of Cardiology
https://www.readbyqxmd.com/read/29563783/changes-in-ventilation-perfusion-during-and-after-an-copd-exacerbation-an-assessment-using-fluid-dynamic-modeling
#16
Bita Hajian, Jan De Backer, Wim Vos, Wouter H van Geffen, Paul De Winter, Omar Usmani, Tony Cahn, Huib Am Kerstjens, Massimo Pistolesi, Wilfried De Backer
Introduction: Severe exacerbations associated with chronic obstructive pulmonary disease (COPD) that require hospitalization significantly contribute to morbidity and mortality. Definitions for exacerbations are very broad, and it is unclear whether there is one predominant underlying mechanism that leads to them. Functional respiratory imaging (FRI) with modeling provides detailed information about airway resistance, hyperinflation, and ventilation-perfusion (V/Q) mismatch during and following an acute exacerbation...
2018: International Journal of Chronic Obstructive Pulmonary Disease
https://www.readbyqxmd.com/read/29481374/can-mathematical-modeling-explain-the-measured-magnitude-of-the-second-gas-effect
#17
Ben Korman, Ranjan K Dash, Philip J Peyton
BACKGROUND: Recent clinical studies suggest that the magnitude of the second gas effect is considerably greater on arterial blood partial pressures of volatile agents than on end-expired partial pressures, and a significant second gas effect on blood partial pressures of oxygen and volatile agents occurs even at relatively low rates of nitrous oxide uptake. We set out to further investigate the mechanism of this phenomenon with the help of mathematical modeling. METHODS: Log-normal distributions of ventilation and blood flow were generated representing the range of ventilation-perfusion scatter seen in patients during general anesthesia...
June 2018: Anesthesiology
https://www.readbyqxmd.com/read/29433570/role-of-atp-sensitive-potassium-channels-on-hypoxic-pulmonary-vasoconstriction-in-endotoxemia
#18
Maurizio Turzo, Julian Vaith, Felix Lasitschka, Markus A Weigand, Cornelius J Busch
BACKGROUND: ATP-regulated potassium channels (KATP) regulate pulmonary vascular tone and are involved in hypoxic pulmonary vasoconstriction (HPV). In patients with inflammation like sepsis or ARDS, HPV is impaired, resulting in a ventilation-perfusion mismatch and hypoxia. Since increase of vascular KATP channel Kir6.1 has been reported in animal models of endotoxemia, we studied the expression and physiological effects of Kir6.1 in murine endotoxemic lungs. We hypothesized that inhibition of overexpressed Kir6...
February 13, 2018: Respiratory Research
https://www.readbyqxmd.com/read/29425776/the-effects-of-hemoglobin-glutamer-200-and-ino-on-pulmonary-vascular-tone-and-arterial-oxygenation-in-an-experimental-acute-respiratory-distress-syndrome
#19
Maria Theresa Voelker, Andreas Bergmann, Thilo Busch, Nora Jahn, Sven Laudi, Katharina Noreikat, Philipp Simon, Sven Bercker
INTRODUCTION: Hemoglobin-based oxygen carriers (HBOC) have been developed as an alternative to blood transfusions. Their nitric-oxide-scavenging properties HBOC also induce vasoconstriction. In acute lung injury, an excess of nitric oxide results in a general vasodilation, reducing oxygenation by impairing the hypoxic pulmonary vasoconstriction. Inhaled nitric oxide (iNO) is used to correct the ventilation perfusion mismatch. We hypothesized that the additional use of HBOC might increase this effect...
April 2018: Pulmonary Pharmacology & Therapeutics
https://www.readbyqxmd.com/read/29398969/bronchopulmonary-sequestration-as-a-cause-of-mismatched-perfusion-defect-on-single-photon-emission-computed-tomography-ventilation-perfusion-scan
#20
Michael A S Kreltszheim, Nick I Brown, Joseph C Lee
We present a 46-year-old female with pleuritic chest pain on a background of pulmonary embolism diagnosed on a single-photon emission computed tomography (SPECT) ventilation-perfusion (V/Q) imaging 3 years earlier. A SPECT V/Q scan detected a mismatched perfusion defect in the posterior basal segment of the right lower lobe, essentially unchanged from a defect identified 3 years earlier. Given the atypical finding, the patient went on to have a computed tomographic pulmonary angiogram. It revealed an intralobar bronchopulmonary sequestration as the cause of the right lower lobe mismatched perfusion defect...
January 2018: World Journal of Nuclear Medicine
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