• Thorax
  • The gas pressure (P) needed to keep equilibrium between the collapsing force of surface tension (γ) and the expanding force of gas in an alveolus of radius r is expressed by the law of Laplace: P = 2 γ r {\displaystyle P={\frac {2\gamma }{r}}} Compliance is the ability of lungs and thorax to expand. (wikipedia.org)
  • Compared to the tissue conductivities of most other soft tissues within the human thorax, lung tissue conductivity is approximately five-fold lower, resulting in high absolute contrast. (wikipedia.org)
  • Alveolar
  • VEGF expression was significantly reduced in the lung, particularly in the alveolar septal cells. (medsci.org)
  • It is hypothesized that the initial or repetitive injury in IPF occurs to the lung cells, called alveolar epithelial cells (AECs, pneumocytes), which line the majority of the alveolar surface. (wikipedia.org)
  • If 'transpulmonary pressure' = 0 (alveolar pressure = intrapleural pressure), such as when the lungs are removed from the chest cavity or air enters the intrapleural space (a pneumothorax), the lungs collapse as a result of their inherent elastic recoil. (wikipedia.org)
  • hysteresis
  • This difference in inflation and deflation volumes at a given pressure is called hysteresis and is due to the air-water surface tension that occurs at the beginning of inflation. (wikipedia.org)
  • Residual Volume
  • Determination of the residual volume is more difficult as it is impossible to "completely" breathe out. (wikipedia.org)
  • Therefore, measurement of the residual volume has to be done via indirect methods such as radiographic planimetry, body plethysmography, closed circuit dilution (including the helium dilution technique) and nitrogen washout. (wikipedia.org)
  • Standard errors in prediction equations for residual volume have been measured at 579 mL for men and 355 mL for women, while the use of 0.24*FVC gave a standard error of 318 mL. (wikipedia.org)
  • function
  • Non-specific bronchial hyperresponsiveness (NSBH) is a known predictor of accelerated rate of decline in lung function in smokers. (bmj.com)
  • Based on these associations, we hypothesised that ADRB2 polymorphisms would be associated with NSBH and BDR as well as an accelerated rate of decline in lung function among smokers. (bmj.com)
  • Contrary to our hypothesis, no ADRB2 allele or haplotype was associated with NSBH, BDR, or rate of decline in lung function. (bmj.com)
  • However, there was a significant negative association between heterozygosity at position 27 and a fast decline in lung function (adjusted odds ratio 0.56, 95% CI 0.40 to 0.78, p=0.0007). (bmj.com)
  • Heterozygosity at position 27 may be protective against an accelerated rate of decline in lung function. (bmj.com)
  • The polymorphism at position 16 does not contribute to the rate of decline in lung function, measures of NSBH, or BDR in smokers. (bmj.com)
  • Polymorphisms in the β 2 adrenergic receptor ( ADRB2 ) have previously been shown to be associated with asthma severity, 8, 9 NSBH, 10, 11 bronchodilator response, 12- 15 and level of lung function. (bmj.com)
  • Airway function measurements and the long-term follow-up of survivors of preterm birth with and with. (biomedsearch.com)
  • Lung-function reference values from Victorian power-industry workmen. (biomedsearch.com)
  • Reference values for a number of lung function tests performed on a group of apparently healthy Victorian power industry workmen are described. (biomedsearch.com)
  • Evolution of lung function during the first year of life in newborn screened cystic fibrosis infants. (nih.gov)
  • THURSDAY, May 22 (HealthDay News) -- Children with sickle cell disease lose lung function faster and more significantly as they age, compared with other children of the same race and age, according to new research. (bio-medicine.org)
  • We expected that children with sickle cell disease would show greater loss of lung function than other children, but this had never been quantified, nor was the pattern of decline clear. (bio-medicine.org)
  • To determine the patterns of loss of lung function, the researchers analyzed 1,357 lung function results that were completed between January 1989 and January 2005 from 413 children with sickle cell disease (SCD) during routine sickle cell clinical visits. (bio-medicine.org)
  • Using statistical modeling, we are able to predict the rate of decline of lung function. (bio-medicine.org)
  • Pulmonary function tests are a group of tests that measure breathing and how well the lungs are functioning. (stlukes-stl.com)
  • This is an important part of lung testing, because the major function of the lung. (stlukes-stl.com)
  • Movements of the grid are viewed by two digital cameras, digitalised, and processed to form a 3D model and can be interrogated to assess lung function. (wikipedia.org)
  • Idiopathic pulmonary fibrosis (IPF) is a type of chronic lung disease characterized by a progressive and irreversible decline in lung function. (wikipedia.org)
  • The diagnosis is based on poor airflow as measured by lung function tests. (wikipedia.org)
  • Pulmonary function testing has diagnostic and therapeutic roles and helps clinicians answer some general questions about patients with lung disease. (wikipedia.org)
  • Pulmonary function testing is a diagnostic and management tool used for a variety of reasons, such as: Chronic shortness of breath Asthma Chronic obstructive pulmonary disease Restrictive lung disease Preoperative testing Impairment or disability Neuromuscular disorders such as Duchenne muscular dystrophy are associated with gradual loss of muscle function over time. (wikipedia.org)
  • Arterial blood gases (ABGs) are a helpful measurement in pulmonary function testing in selected patients. (wikipedia.org)
  • Reference Values for Lung Function tests in Females. (wikipedia.org)
  • However, two commercial f-EIT devices for monitoring lung function in intensive care patients have been introduced just recently. (wikipedia.org)
  • transplantation
  • Chronic lung allograft dysfunction (CLAD) is, in one sense, a term without a true consensus definition, although its common usage in the field of lung transplantation implies a base understanding throughout the community that it describes a lung allograft that does not work (well) [ 1 ]. (ersjournals.com)
  • Perhaps this bespeaks our simplistic understanding of the root causative mechanisms, but emphasises there is still much to learn about this dominant complication of lung transplantation, which is the major risk factor for death in those who survive the perioperative period. (ersjournals.com)
  • Although the finding of a poor outcome with gas trapping has not been widely reported previously after lung transplantation, it makes biological sense and resonates with conventional knowledge that accepts that gas trapping is associated with an increased risk of dynamic hyperinflation (an increase in TLC) and thereby an increase in mechanical load on the inspiratory muscles, reduced mechanical advantage and increased oxygen cost of breathing [ 8 ]. (ersjournals.com)
  • Lung transplantation may also be an option. (wikipedia.org)
  • Some people may benefit from long-term oxygen therapy or lung transplantation. (wikipedia.org)
  • alveoli
  • This also helps all alveoli in the lungs expand at the same rate, as one that expands more quickly will experience a large rise in surface tension slowing its rate of expansion. (wikipedia.org)
  • This is due to the fact that a high compliant lung results in many collapsed alveoli which makes inflation difficult. (wikipedia.org)
  • Gas exchange in the lungs occurs in millions of small air sacs called alveoli in mammals and reptiles, but atria in birds. (wikipedia.org)
  • A system such as this creates dead space, a volume of air (about 150 ml in the adult human) that fills the airways after exhalation and is breathed back into the alveoli before environmental air reaches them. (wikipedia.org)
  • Since atmospheric pressure is relatively constant, pressure in the lungs must be higher or lower than atmospheric pressure for air to flow between the atmosphere and the alveoli. (wikipedia.org)
  • Diagnosis
  • Diagnosis requires ruling out other potential causes and may be supported by a CT scan or lung biopsy. (wikipedia.org)
  • Assessment of "velcro" crackles on lung auscultation is a practical way to improve the earlier diagnosis of IPF. (wikipedia.org)
  • They use radiographic techniques to view vasculature of the lungs and heart to assist with diagnosis. (wikipedia.org)
  • cystic fibrosis
  • The pulmonologist begins the diagnostic process with a general review focusing on: hereditary diseases affecting the lungs (cystic fibrosis, alpha 1-antitrypsin deficiency) exposure to toxins (tobacco smoke, asbestos, exhaust fumes, coal mining fumes) exposure to infectious agents (certain types of birds, malt processing) an autoimmune diathesis that might predispose to certain conditions (pulmonary fibrosis, pulmonary hypertension) Physical diagnostics are as important as in the other fields of medicine. (wikipedia.org)
  • restrictive
  • This pattern of decline confirmed a restrictive pattern with an average loss of 2 percent per year of total lung capacity. (bio-medicine.org)
  • The results (in particular FEV1/FVC and FRC) can be used to distinguish between restrictive and obstructive pulmonary diseases: Lung capacity can be expanded through flexibility exercises such as yoga, breathing exercises, and physical activity. (wikipedia.org)
  • Compliance decreases in the following cases: Supine position Laparoscopic surgical interventions Severe restrictive pathologies Chronic restrictive pathologies Hydrothorax Pneumothorax High standing of a diaphragm Acute asthma attacks [Increased compliance also occurs, for an unclear reason] Lung compliance at the US National Library of Medicine Medical Subject Headings (MeSH) Compliance Nikischin W, Gerhardt T, Everett R, Bancalari E (1998). (wikipedia.org)
  • In restrictive lung disease the vital capacity is decreased. (wikipedia.org)
  • Diseases
  • Institute of Tuberculosis and Lung Diseases, Warsaw, Poland. (biomedsearch.com)
  • Despite aggressive public health initiatives aimed at discouraging the use of cigarettes, smoking-related lung diseases remain a significant cause of disability and death in the United States. (clinicaltrials.gov)
  • expiratory
  • RESULTS: End expiratory chest wall volume increased by a mean (SE) of 592 (80) ml in 12 patients (hyperinflators) but decreased by 462 (103) ml in eight (euvolumics). (biomedsearch.com)
  • This can be done very simply on a single sheet of paper by recording the FEV1 (forced expiratory volume in one second) value at age of test. (personneltoday.com)
  • PEEP = Positive End Expiratory Pressure: C d y n = V T P I P − P E E P {\displaystyle C_{dyn}={\frac {V_{T}}{PIP-PEEP}}} Alterations in airway resistance, lung compliance and chest wall compliance influence Cdyn. (wikipedia.org)
  • Compliance
  • the decrease in dynamic lung compliance plays a definite but less important role. (biomedsearch.com)
  • Lung compliance is defined as the volume change per unit of pressure change across the lung. (wikipedia.org)
  • Pulmonary surfactant thus greatly reduces surface tension, increasing compliance allowing the lung to inflate much more easily, thereby reducing the work of breathing. (wikipedia.org)
  • In clinical practice it is separated into two different measurements, static compliance and dynamic compliance. (wikipedia.org)
  • Static lung compliance is the change in volume for any given applied pressure. (wikipedia.org)
  • Dynamic lung compliance is the compliance of the lung at any given time during actual movement of air. (wikipedia.org)
  • Low compliance indicates a stiff lung (one with high elastic recoil) and can be thought of as a thick balloon - this is the case often seen in fibrosis. (wikipedia.org)
  • Compliance is highest at moderate lung volumes, and much lower at volumes which are very low or very high. (wikipedia.org)
  • that is, the compliance is different on inspiration and expiration for identical volumes. (wikipedia.org)
  • Dynamic compliance is always lower than or equal to static lung compliance because PIP − PEEP is always greater than Pplat − PEEP. (wikipedia.org)
  • Low compliance indicates a stiff lung and means extra work is required to bring in a normal volume of air. (wikipedia.org)
  • oxygen
  • This test allows the doctor to estimate how well the lungs move oxygen from the air into the bloodstream. (stlukes-stl.com)
  • the Himalayas) that person can develop a condition called altitude sickness because their lungs remove adequate amounts of carbon dioxide but they do not take in enough oxygen. (wikipedia.org)
  • The technique is based on the assumptions that the nitrogen concentration in the lungs is 78% and in equilibrium with the atmosphere, that the patient inhales 100% oxygen and that the oxygen replaces all of the nitrogen in the lungs. (wikipedia.org)
  • collapse
  • Even though the baby is not using her lungs, an ocillating ventilator maybe still be used to keep some air in the lungs so that they do not fully collapse while not being used. (wikipedia.org)
  • To prevent atelectasis (collapse of the lung) at the end of expiration. (wikipedia.org)
  • Adult
  • The average total lung capacity of an adult human male is about 6 litres of air. (wikipedia.org)
  • A typical adult human spirogram with the names given to the various excursions in volume the lungs can undergo is illustrated below (Fig. 3): Not all the air in the lungs can be expelled during maximally forced exhalation. (wikipedia.org)
  • pressures
  • To test this hypothesis, we studied four experienced normal subjects during fatiguing breathing tasks performed over a range of pressures and flows and at two different lung volumes. (biomedsearch.com)
  • Stroke Volume
  • assuming a heart rate of 70 beats/min, the stroke volume would be approximately 70 mL. (wikipedia.org)
  • 2D measurement of the diameter (d) of the aortic annulus allows calculation of the flow cross-sectional area (CSA), which is then multiplied by the VTI of the Doppler flow profile across the aortic valve to determine the flow volume per beat (stroke volume, SV). (wikipedia.org)
  • clinical
  • Differences such as measurement technique, equipment calibration, occupational factors, and selection bias must be considered when reference values from published reports are used for clinical or epidemiological purposes. (biomedsearch.com)
  • The group suggested that non-invasive technique measurements were of sufficient accuracy to be tried in clinical practice. (wikipedia.org)
  • compute
  • Online calculators are available that can compute predicted lung volumes, and other spirometric parameters based on a patient's age, height, weight, and ethnic origin for many reference sources. (wikipedia.org)
  • The digital information was used to compute automatically the volume of the trunk and the position of any point on its surface and its cross-sectional shape at any level. (wikipedia.org)