• It is concluded that hypoxic pulmonary vasoconstriction is often a critical determinant of hypoxemia and/or pulmonary hypertension. (nih.gov)
  • Pulmonary Hypertension Pulmonary hypertension is increased pressure in the pulmonary circulation. (msdmanuals.com)
  • In pulmonary hypertension, pulmonary vessels may become constricted. (msdmanuals.com)
  • In contrast, during global alveolar hypoxia, HPV leads to pulmonary hypertension. (ersjournals.com)
  • Under these conditions, HPV can increase pulmonary vascular resistance and subsequently right heart afterload and may lead, in concert with pulmonary vascular remodelling processes, to fixed pulmonary hypertension and right heart insufficiency. (ersjournals.com)
  • Understanding HPV may help us to develop therapeutic strategies for impaired gas exchange due to attenuated HPV, as well as for pulmonary hypertension due to generalised HPV. (ersjournals.com)
  • Introduction: Submaximal exercise gas exchange may be a useful tool to track responses to therapy in pulmonary arterial hypertension (PAH) patients. (elsevierpure.com)
  • While the maintenance of ventilation/perfusion ratio during regional obstruction of airflow is beneficial, HPV can be detrimental during global alveolar hypoxia which occurs with exposure to high altitude, where HPV causes a significant increase in total pulmonary vascular resistance, and pulmonary arterial pressure, potentially leading to pulmonary hypertension and pulmonary edema. (wikipedia.org)
  • Mixed cardiac and pulmonary disorders are also common sources of dyspnea 6 , 7 and include COPD with pulmonary hypertension and cor pulmonale, deconditioning, pulmonary emboli and trauma. (aafp.org)
  • 12 - 14 Pulmonary arterial hypertension is also common 15 and may worsen with exercise. (bmj.com)
  • Persistent pulmonary hypertension of the newborn (PPHN) is defined as the failure of the normal circulatory transition that occurs after birth. (medscape.com)
  • It is a syndrome characterized by marked pulmonary hypertension that causes hypoxemia secondary to right-to-left shunting of blood at the foramen ovale and ductus arteriosus. (medscape.com)
  • Idiopathic persistent pulmonary hypertension of the newborn can present without signs of acute perinatal distress. (medscape.com)
  • In contrast to adult primary pulmonary hypertension, the newborn syndrome is not defined by a specific pressure of the pulmonary circulation. (medscape.com)
  • The contributions of hypoxic pulmonary vasoconstriction to both homeostasis and pathophysiology are quantitated for atelectasis, pneumonia, sepsis, pulmonary embolism, chronic obstructive pulmonary disease and adult respiratory distress syndrome. (nih.gov)
  • Pulmonary Embolism (PE) Pulmonary embolism (PE) is the occlusion of pulmonary arteries by thrombi that originate elsewhere, typically in the large veins of the legs or pelvis. (msdmanuals.com)
  • Risk factors for pulmonary embolism are. (msdmanuals.com)
  • Medline OVID1966-2005 Feb week 1 and Embase OVID 1980-2005 week 7: (exp pulmonary embolism/OR pulmonary embolus.mp. (bmj.com)
  • Cvitac O . Improved use of arterial blood gas analysis in suspected pulmonary embolism. (bmj.com)
  • Arterial blood gas analysis in the assessment of suspected acute pulmonary embolism. (bmj.com)
  • Use of the alveolar-arterial oxygen gradient in the assessment of acute pulmonary embolism. (bmj.com)
  • Diagnostic value of gas exchange tests in patients with clinical suspicion of pulmonary embolism. (bmj.com)
  • Arterial blood gas analysis and alveolar-arterial oxygen gradient in diagnosis and prognosis of elderly patients with suspected pulmonary embolism. (bmj.com)
  • Diagnostic value of arterial blood gas measurement in suspected pulmonary embolism. (bmj.com)
  • Colloquially known as blood clots, deep vein thrombosis (DVT) and pulmonary embolism (PE) are forms of venous thromboembolism (VTE). (medscape.com)
  • It can also be classified according to its severity, which is determined on the basis of the presence or absence of hemodynamic instability, the presence or absence of respiratory symptoms, and the anatomic location of the embolism in the pulmonary vasculature. (medscape.com)
  • Role of hypoxic pulmonary vasoconstriction in pulmonary gas exchange and blood flow distribution. (nih.gov)
  • Hypoxic pulmonary vasoconstriction (HPV), also known as the von Euler-Liljestrand mechanism, is an essential response of the pulmonary vasculature to acute and sustained alveolar hypoxia. (ersjournals.com)
  • Hypoxic pulmonary vasoconstriction (HPV), also known as the von Euler-Liljestrand mechanism, is an intrinsic mechanism of the pulmonary vasculature in response to alveolar hypoxia, to match ventilation to perfusion and optimise pulmonary gas exchange ( figure 1 ). (ersjournals.com)
  • Hypoxic pulmonary vasoconstriction optimises gas exchange by matching perfusion to ventilation. (ersjournals.com)
  • Hypoxic pulmonary vasoconstriction (HPV), also known as the Euler-Liljestrand mechanism, is a physiological phenomenon in which small pulmonary arteries constrict in the presence of alveolar hypoxia (low oxygen levels). (wikipedia.org)
  • The classical explanation of HPV involves inhibition of hypoxia-sensitive voltage-gated potassium channels in pulmonary artery smooth muscle cells leading to depolarization. (wikipedia.org)
  • This contrasts with the classical explanation of HPV which presumes that hypoxia is sensed at the pulmonary artery smooth muscle cell itself. (wikipedia.org)
  • We created a model of right-sided heart failure by pulmonary artery banding in ten dogs for a duration of more than 3 months. (unboundmedicine.com)
  • After a complete ligation of the main pulmonary artery, five of the nine dogs survived more than 6 h. (unboundmedicine.com)
  • Arteries transport oxygenated blood (except for the pulmonary artery) to various parts of the body, delivering nutrients and oxygen to the tissues. (proprofs.com)
  • Chronic Obstructive Pulmonary Disease (COPD) Chronic obstructive pulmonary disease (COPD) is airflow limitation caused by an inflammatory response to inhaled toxins, often cigarette smoke. (msdmanuals.com)
  • Although many natural disease processes may involve inadequate uptake and/or delivery of oxygen (eg, chronic obstructive pulmonary disease [COPD]), the term "asphyxia" is generally reserved for conditions related to abnormal atmosphere and mechanical and chemical effects directly leading to the aforementioned abnormalities. (medscape.com)
  • The course of chronic obstructive pulmonary disease (COPD) is characterized by acute exacerbations, commonly requiring hospital admission and often associated with the development of respiratory failure. (atsjournals.org)
  • The most common obstructive causes are chronic obstructive pulmonary disease (COPD) and asthma. (aafp.org)
  • Background: Passive training of specific locomotor muscle groups by means of neuromuscular electrical stimulation (NMES) might be better tolerated than whole body exercise in patients with severe chronic obstructive pulmonary disease (COPD). (bmj.com)
  • Exercise intolerance is a hallmark of chronic obstructive pulmonary disease (COPD) and is commonly associated with reduced quality of life and increased utilisation of healthcare resources. (bmj.com)
  • 4- 7 Exercise training, typically as a component of pulmonary rehabilitation, has been shown to improve exercise tolerance in COPD. (bmj.com)
  • Although exercise training effectively improves exercise capacity and health related quality of life in patients with chronic obstructive pulmonary disease (COPD), 4 its role in patients with ILD is unclear. (bmj.com)
  • New study revealed that the level of evidence in favor of pulmonary rehabilitation (PR) in COPD is high. (medindia.net)
  • In Germany, 13.2% of the population older than 40 are affected by chronic obstructive pulmonary disease (COPD). (medindia.net)
  • By 2020, chronic obstructive pulmonary disease (COPD) will be the third most common cause of morbidity and mortality worldwide. (medindia.net)
  • Childhood measles was found to be associated to increase the risk of chronic obstructive pulmonary disease (COPD) later in life, especially in middle age. (medindia.net)
  • Pulmonary exercise testing is helpful in predicting the course of disease and long-term survival in people with COPD. (ucsd.edu)
  • Ventilation, cardiac output, and the distribution of ventilation-perfusion (V˙ a /Q˙ ) ratios were measured using the multiple inert gas elimination technique breathing air and then 100% oxygen through a nose mask. (atsjournals.org)
  • Ventilation/perfusion studies have shown no clinically significant effects on pulmonary gas exchange or arterial oxygen tension. (theodora.com)
  • MR imaging of pulmonary perfusion using hyperpolarized 129Xe dissolved in an injectable carrier. (mpg.de)
  • MR imaging of pulmonary perfusion and gas exchange by intravenous injection of hyperpolarized 129Xe. (mpg.de)
  • This situation may occur at high altitude or during respiratory diseases, including chronic obstructive pulmonary disease, sleep apnoea and fibrosis, and during failure of ventilation due to neurological diseases. (ersjournals.com)
  • The detailed mechanisms of oxygen-induced hypercapnia were examined in 22 patients during an acute exacerbation of chronic obstructive pulmonary disease. (atsjournals.org)
  • Postnatal hyperoxia exposure in rodents is a well-established model of chronic lung disease of prematurity, and also recapitulates the pulmonary vascular, cardiovascular, and renal phenotype of premature birth. (frontiersin.org)
  • Chronic obstructive pulmonary disease affects millions of people worldwide and is responsible for numerous deaths due to complications. (medindia.net)
  • Observations during influenza epidemics indicate that most influenza-related deaths occur among: (1) persons older than 65 years of age and (2) persons with chronic, underlying disorders of the cardiovascular, pulmonary, and/or renal systems, as well as those with metabolic diseases (including diabetes mellitus), severe anemia, and/or compromised immune function. (cdc.gov)
  • ABSTRACT Pulmonary rehabilitation is a tool that is receiving more acceptance in chronic lung diseases. (who.int)
  • A retrospective study was made in Riyadh, Saudi Arabia, on the impact of pulmonary rehabilitation on respiratory parameters and health care utilization in a group of outpatients with chronic lung diseases other than chronic obstructive pulmonary disease. (who.int)
  • Idiopathic Pulmonary Fibrosis Idiopathic pulmonary fibrosis (IPF), the most common form of idiopathic interstitial pneumonia, causes progressive pulmonary fibrosis. (msdmanuals.com)
  • [ 6 ] In addition, although data regarding the association between MUC5B promoter polymorphism and idiopathic pulmonary fibrosis appear to be clear, the data are mixed about the MUC5B promoter variant being a potential genetic risk factor for asbestosis. (medscape.com)
  • and whether patients with idiopathic pulmonary fibrosis (IPF) had similar responses to those with other types of ILD. (bmj.com)
  • Patients with idiopathic pulmonary fibrosis (IPF) generally demonstrate greater abnormalities of exercise induced gas exchange than those with other forms of ILD. (bmj.com)
  • The DLCO increase in heart failure presumably because the increased pulmonary venous and arterial pressure recruits additional pulmonary microvessels. (msdmanuals.com)
  • The Pulmonary Fibrosis Foundation rates among top charities in the U.S. The PFF has a four-star rating from Charity Navigator and is an accredited charity by the Better Business Bureau (BBB) Wise Giving Alliance. (pulmonaryfibrosis.org)
  • Lung histopathology reveals interstitial infiltration with mononuclear cells, well-defined noncaseating granulomas (sometimes with multinucleated giant cells and calcific inclusions), and varying degrees of pulmonary fibrosis (Meyer 1994). (cdc.gov)
  • Restrictive lung problems include extrapulmonary causes such as obesity, spine or chest wall deformities, and intrinsic pulmonary pathology such as interstitial fibrosis, pneumoconiosis, granulomatous disease or collagen vascular disease. (aafp.org)
  • Blue arrows indicate the constriction of pulmonary arteries, black arrows the direction of blood flow. (ersjournals.com)
  • Capillaries, on the other hand, are the smallest blood vessels that connect arteries and veins, allowing for the exchange of oxygen, nutrients, and waste products between the blood and the surrounding tissues. (proprofs.com)
  • Pulmonary function was adequate in most bears, but it is advisable to have supplemental oxygen available in case of hypoxemia. (vin.com)
  • The oxygen sensing and signal transduction machinery is located in the pulmonary arterial smooth muscle cells (PASMCs) of the pre-capillary vessels, albeit the physiological response may be modulated in vivo by the endothelium. (ersjournals.com)
  • The MediPines AGM100 is an FDA-cleared, advanced pulmonary gas exchange technology that exclusively provides Oxygen Deficit, a surrogate for the alveolar to arterial oxygen difference (AaDO2), as well as blood oxygen level (gPaO 2 ), PETCO 2 , and other sensitive measurements of pulmonary gas exchange. (my.id)
  • The process might initially seem counterintuitive, as low oxygen levels might theoretically stimulate increased blood flow to the lungs to increase gas exchange. (wikipedia.org)
  • Traditionally, the conditions leading to asphyxia have included breathing an oxygen-deficient atmosphere and/or interference with the act of breathing (ie, inhaling and exhaling) and/or respiration (ie, gas exchange and the utilization of oxygen). (medscape.com)
  • Arterial blood gas at rest in the supine position and in ambient air showed an increased alveolar-arterial oxygen tension difference ( P A-aO 2 ), since arterial carbon dioxide tension ( P aCO 2 ) was 26 mmHg and arterial oxygen tension ( P aO 2 ) was 72 mmHg. (ersjournals.com)
  • In order to determine whether daily exposure to methylene chloride (75092) vapors affects hemoglobin affinity for oxygen and/or pulmonary function, four healthy young males aged 22 to 24 years were exposed for 7-1/2 hours per day for 26 days in an environmental chamber over 6 consecutive weeks to various concentrations (0 to 50ppm) of methylene-chloride vapor. (cdc.gov)
  • Effects of the vapor on pulmonary airways, pulmonary gas exchange, the regulation of pulmonary ventilation and hemoglobin affinity for oxygen were examined. (cdc.gov)
  • Arterial blood gas levels (through an indwelling line [eg, umbilical arterial catheter or preductal peripheral arterial line]): To assess the pH, partial pressure of carbon dioxide (PaCO 2 ) and the partial pressure of oxygen (PaO 2 ) which might be higher in the preductal arterial line. (medscape.com)
  • During gas exchange oxygen moves from the lungs to the bloodstream. (medlineplus.gov)
  • Gas exchange allows the body to replenish the oxygen and eliminate the carbon dioxide. (medlineplus.gov)
  • They are responsible for the exchange of oxygen, nutrients, and waste products between the blood and surrounding tissues. (proprofs.com)
  • This blood is pumped down to the right ventricle via the tricuspid valve and eventually through the pulmonic valve, leading to the pulmonary trunk that takes the oxygen deprived blood to the lungs for gas exchange. (medscape.com)
  • Once gas exchange occurs in the lung tissue, the oxygen-laden blood is carried to the left atrium via the pulmonary veins, hence completing the pulmonary circuit (see the image above). (medscape.com)
  • Hypercapnia and hypoxemia may coexist, though some disorders may affect gas exchange differentially. (medscape.com)
  • 2001). For many patients with CBD, results of resting pulmonary function tests, including spirometry values, lung volumes, and carbon monoxide-diffusing capacity (DLCO), are normal but resting and exercise arterial blood gas levels indicate hypoxemia. (cdc.gov)
  • As severe hypoxemia, we immediately started inhaled nitric oxide (iNO) that improved significantly pulmonary gas exchange. (minervamedica.it)
  • Suspect PPHN whenever the level of hypoxemia is out of proportion to the level of pulmonary disease. (medscape.com)
  • Endoscopic techniques that allow visualization of the airways of patients with pulmonary maladies have become a mainstay of medical treatment. (lww.com)
  • Gas dilution techniques determine functional residual capacity (FRC) by measuring areas of the lung that readily communicate with the central airways during tidal breathing. (ersjournals.com)
  • 1981). On the other hand, moderately to poorly water soluble vapors (e.g., chloroform, methylene chloride, trichloro- ethylene, styrene, naphthalene, and butadiene) are not efficiently extracted in the extrathoracic region and penetrate the nasal cavity and conducting airways to reach the gas-exchange region. (cdc.gov)
  • Optimal V/Q matching occurs when the ratio of the volume of gas to the volume of blood entering the lungs approximates 1. (medscape.com)
  • DLCO test (diffusing capacity): Assesses how well lungs exchange gases. (ucsd.edu)
  • Pulmonary exercise tests allow the physician to evaluate the lungs and heart under conditions of increased metabolic demand. (ucsd.edu)
  • Of those with pulmonary function abnormalities, one third of patients present with an obstructive pattern, one fourth with a restrictive pattern of decreased lung volumes, one third with an isolated decreased DLCO, and the remainder have a mixed pattern of obstruction and restriction with varying amounts of gas exchange abnormality (Newman and Maier 2001). (cdc.gov)
  • Pulmonary causes include obstructive and restrictive processes. (aafp.org)
  • Une étude rétrospective a été menée à Riyad (Arabie saoudite) pour connaître l'impact de la rééducation pulmonaire d'une part sur les paramètres respiratoires d'un groupe de patients en consultation externe pour des affections pulmonaires chroniques autres que la bronchopneumopathie chronique obstructive (BPCO) et d'autre part sur leur utilisation des soins de santé. (who.int)
  • The exercise capacity test reveals gas exchange or ventilatory abnormalities, including an elevation in the dead space-to-tidal volume ratio, in most patients with CBD. (cdc.gov)
  • BACKGROUND: We hypothesized that in morbid obesity, pulmonary gas exchange abnormalities will worsen when supine and that bariatric surgery (BS) will mitigate this effect. (northumbria.ac.uk)
  • DLCO is measured by sampling end-expiratory gas for carbon monoxide (CO) after patients inspire a small amount of carbon monoxide, hold their breath, and exhale. (msdmanuals.com)
  • Conclusion: Gas exchange variables measured during light submaximal exercise, such as P ET CO 2 and V E /VCO 2 , may be able to better detect small changes in functional status following treatment and could, therefore, be a useful tool to track disease severity in PAH patients. (elsevierpure.com)
  • A short cut review was carried out to establish the diagnostic utility of arterial blood gas analysis in patients with suspected pulmonary embolus. (bmj.com)
  • Noncardiac or nonpulmonary disease must be considered in patients with minimal risk factors for pulmonary disease and no clinical evidence of cardiac or pulmonary disease. (aafp.org)
  • The vast majority of HPS patients (82%) initially present with features of their liver disease, while a minority (18%) present with lung (pulmonary) complaints first. (rarediseases.org)
  • Ergometers are not recommended for patients that have poor coordination, have lower extremity musculoskeletal disease, or are performing a gas exchange study. (suntechmed.com)
  • Physicians order pulmonary exercise tests for patients who are easily short of breath. (ucsd.edu)
  • Despite not having a standardized measurement parameter, the excess of neutrophil extracellular traps corresponds conception, manuscript to the severity of tissue damage observed in patients with respiratory tract infections, revealing the important prognostic role design, literature search, data of the neutrophil response and NETosis process in pulmonary infectious diseases. (bvsalud.org)
  • The diffusing capacity for carbon monoxide (DLCO) is a measure of the ability of gas to transfer from the alveoli across the alveolar epithelium and the capillary endothelium to the red blood cells. (msdmanuals.com)
  • Pulmonary Diffusing Capacity" is a descriptor in the National Library of Medicine's controlled vocabulary thesaurus, MeSH (Medical Subject Headings) . (umassmed.edu)
  • This graph shows the total number of publications written about "Pulmonary Diffusing Capacity" by people in this website by year, and whether "Pulmonary Diffusing Capacity" was a major or minor topic of these publications. (umassmed.edu)
  • Below are the most recent publications written about "Pulmonary Diffusing Capacity" by people in Profiles. (umassmed.edu)
  • The DLCO depends not only on the area and thickness of the blood-gas barrier but also on the volume of blood in the pulmonary capillaries. (msdmanuals.com)
  • In erythrocythemia, DLCO is increased because hematocrit is increased and because of the vascular recruitment that occurs with increased pulmonary pressures due to increased viscosity. (msdmanuals.com)
  • A 28 year old woman presents to the Emergency Department with acute suspected pulmonary embolus (PE). (bmj.com)
  • Recent studies show that lidocaine administered intravenously improves pulmonary function and protects pulmonary tissue in pigs under hemorrhagic shock, sepsis and under pulmonary surgery. (bvsalud.org)
  • This article reviews assisted ventilation of the newborn, highlighting the concepts of pulmonary mechanics, gas exchange, respiration control, and lung injury that can be used to enhance conventional mechanical ventilation (CMV) so as to improve survival and reduce adverse effects. (medscape.com)
  • The physiology of normal respiration and gas exchange is complex, and that of dyspnea is even more so. (aafp.org)
  • Objective To determine the ability of lung ultrasound (LUS) of the dependent region to detect real-time changes in lung volume, identify opening and closing pressures of the lung, and detect pulmonary hysteresis. (bmj.com)
  • Capillaries carry blood to tissue cells and are the exchange sites of nutrients, gases, wastes, etc. (medscape.com)
  • Pulmonary Rehabilitation (PR) is an individual, patient-centered therapy program that is based on a comprehensive diagnostic evaluation and consists of patient education/training, physical exercise, and behavioral training. (medindia.net)
  • Initial number of emergency department visits and hospital admissions and use of prednisone and antibiotics were significantly associated with adherence to the pulmonary rehabilitation programme. (who.int)
  • Pulmonary-hematologic studies on humans during exposure to methylene chloride. (cdc.gov)
  • Pulmonary angiography, the gold standard diagnostic tool in PE, has unacceptably high mortality and morbidity. (bmj.com)
  • Arterial blood gas analysis alone is of limited diagnostic utility in suspected PE. (bmj.com)
  • Repeat pulmonary function and gas exchange tests. (cdc.gov)
  • In selected cases where the test results are inconclusive or require clarification, complete pulmonary function testing, arterial blood gas measurement, echocardiography and standard exercise treadmill testing or complete cardiopulmonary exercise testing may be useful. (aafp.org)
  • Standard pulmonary function tests were also performed. (researchgate.net)
  • What is a Pulmonary Function Test? (ucsd.edu)
  • A pulmonary function test is a non-invasive test used to determine a patient's lung function and source of shortness of breath. (ucsd.edu)
  • In phase II, pulmonary function of 20 subjects was measured whilst at rest and exercising to the predetermined workload while breathing ambient air first, then breathing through N95-mask materials. (biomedcentral.com)
  • The pulmonary circuit is on the right side of the heart and serves the function of gas exchange. (medscape.com)
  • Pulmonary surfactant is an essential lipid-protein complex that stabilizes the respiratory units (alveoli) involved in gas exchange. (nih.gov)
  • Para la elaboración de este artículo de revisión narrativa se consultaron las publicaciones disponibles a neutrófilos en el través de una búsqueda automatizada en las bases de datos de PubMed, Scopus y Embase. (bvsalud.org)
  • Clinical Medicine Insights: Circulatory, Respiratory and Pulmonary Medicine , 4 (1), 35-40. (elsevierpure.com)
  • Recently it was proposed that hypoxia is sensed at the alveolar/capillary level, generating an electrical signal that is transduced to pulmonary arterioles through gap junctions in the pulmonary endothelium to cause HPV. (wikipedia.org)
  • High-altitude mountaineering can induce pulmonary hypoxia due to decreased atmospheric pressure. (wikipedia.org)
  • Newborns are vulnerable to impaired gas exchange because of their high metabolic rate, propensity for decreased functional residual capacity (FRC), decreased lung compliance, increased resistance, and potential for right-to-left shunts through the ductus arteriosus, foramen ovale, or both. (medscape.com)
  • Breathing through N95 mask materials have been shown to impede gaseous exchange and impose an additional workload on the metabolic system of pregnant healthcare workers, and this needs to be taken into consideration in guidelines for respirator use. (biomedcentral.com)
  • Further study is required to determine the clinical usefulness of these gas exchange variables. (elsevierpure.com)
  • However, the important clinical observation is the lack of gas exchange deterioration when supine, which may have implications for critical care and anesthesia settings. (northumbria.ac.uk)
  • Clinical Fellowship, Pulmonary Medicine, Univ. (mdanderson.org)
  • The differential diagnosis is composed of four general categories: cardiac, pulmonary, mixed cardiac or pulmonary, and noncardiac or nonpulmonary. (aafp.org)
  • The broad differential diagnosis of dyspnea contains four general categories: cardiac, pulmonary, mixed cardiac or pulmonary, and noncardiac or nonpulmonary ( Table 1 ) . (aafp.org)
  • The diagnosis is confirmed regardless of the pulmonary arterial pressure, as long as it is accompanied by a right-to-left shunt and absence of congenital heart disease. (medscape.com)
  • Assist in a pulmonary diagnosis. (ucsd.edu)
  • Most cases of dyspnea are due to cardiac or pulmonary disease, which is readily identified with a careful history and physical examination. (aafp.org)
  • Although MBNW can be performed easily, the considerable change in gas viscosity during the washout manoeuvre significantly affects the accuracy of the gas flow ( V ′) measurement by pneumotachography 3 , 4 . (ersjournals.com)