• The underlying causes include: Increased airways resistance (chronic obstructive pulmonary disease, asthma, suffocation) Reduced breathing effort (drug effects, brain stem lesion, extreme obesity) A decrease in the area of the lung available for gas exchange (such as in chronic bronchitis) Neuromuscular problems (Guillain-Barré syndrome, motor neuron disease) Deformed (kyphoscoliosis), rigid (ankylosing spondylitis), or flail chest. (wikipedia.org)
  • Acute exacerbations of chronic obstructive pulmonary disease (COPD) are important events in the history of this debilitating lung condition. (dovepress.com)
  • Chronic obstructive pulmonary disease (COPD) is a global health problem and is expected to be the third leading cause of mortality worldwide by 2020. (dovepress.com)
  • This failure in ventilation may be caused by depression of the central respiratory center by cerebral disease or drugs, inability to ventilate adequately due to neuromuscular disease (e.g., myasthenia gravis, amyotrophic lateral sclerosis, Guillain-Barré syndrome, muscular dystrophy), or airway obstruction related to asthma or chronic obstructive pulmonary disease (COPD) exacerbation. (wikipedia.org)
  • Chronic obstructive pulmonary disease includes chronic bronchitis and previously termed emphysema, can be related to smoking or exposure to harmful substances such as coal dust, asbestos fibres and crystalline silica dust. (wikipedia.org)
  • 8 However, certain forms of ALI can cause alterations of the pulmonary hemodynamics and blood flow as a result of different factors such as microembolism, hypoxic vasoconstriction, and a secondary response to mediator release, 9 which may cause changes in the dispersion of pulmonary blood flow and interfere with the effect of intrapulmonary-instilled perfluorocarbons. (asahq.org)
  • The authors hypothesized that ventilation-perfusion (VA/Q) inequality is more pronounced in patients with MVD before and after induction of anesthesia and during and after surgery when extracorporeal circulation (ECC) is used. (biomedsearch.com)
  • Hyperthermochemotherapeutic perfusion model through isolated pelvic vessels was developed to evaluate the leakage of hyperthermia and drugs (such as adriamycin) from the isolated pelvic circulation to systemic circulation and its associated side/toxic effects. (biomedsearch.com)
  • On the other hand, HAPE may be due to general vasoconstriction in the pulmonary circulation (normally a response to regional ventilation-perfusion mismatches) which, with constant or increased cardiac output, also leads to increases in capillary pressures. (wikipedia.org)
  • As smaller pulmonary emboli tend to lodge in more peripheral areas without collateral circulation they are more likely to cause lung infarction and small effusions (both of which are painful), but not hypoxia, dyspnea or hemodynamic instability such as tachycardia. (wikipedia.org)
  • With conventional ventilation where tidal volumes (VT) exceed dead space(VDEAD), gas exchange is largely related to bulk flow of gas to the alveoli. (wikipedia.org)
  • In the ventilation phase of the test, a gaseous radionuclide such as xenon or technetium DTPA in an aerosol form is inhaled by the patient through a mouthpiece or mask that covers the nose and mouth. (wikipedia.org)
  • Potential limitations of oxygen-enhanced lung MRI are the relatively low signal enhancement corresponding to a T 1 reduction of about 10 %, and the complex contrast mechanism with contributions due to ventilation, perfusion, and oxygen-diffusion properties of the lung. (springer.com)
  • A low PaO2 indicates that the patient's current minute ventilation (whether high or normal) is not enough to allow adequate oxygen diffusion into the blood. (wikipedia.org)
  • Method for determination of pulmonary gas exchange in connection with birth. (biomedsearch.com)
  • An apparatus built on the "open" system for determination of pulmonary gas exchange in the newborn infant after birth is described. (biomedsearch.com)
  • A lower V/Q ratio (with respect to the expected value for a particular lung area in a defined position) impairs pulmonary gas exchange and is a cause of low arterial partial pressure of oxygen (paO 2 ). (wikipedia.org)
  • Impairment of pulmonary gas exchange secondary to general anesthesia, cardiac surgery, and ECC are comparable for patients undergoing myocardial revascularization or mitral valve surgery. (biomedsearch.com)
  • Gas exchange after pulmonary thromboemoblization in dogs. (ahajournals.org)
  • Gas exchange following experimental pulmonary thromboembolization was studied with an inert gas elimination technique in 17 dogs. (ahajournals.org)
  • With high frequency ventilation, the tidal volumes used are smaller than anatomical and equipment dead space and therefore alternative mechanisms of gas exchange occur. (wikipedia.org)
  • A CT pulmonary angiogram (CTPA) with radiocontrast can alternatively be performed, although this can result in a greater radiation dose to the patient. (wikipedia.org)
  • In order to decrease the radiation exposure in pregnant patients, the total radioactivity administered may be decreased or the ventilation phase omitted. (wikipedia.org)
  • Inclusion criteria were patients in sinus rhythm on controlled ventilation with signs of circulatory failure secondary to presumed hypovolemia. (hindawi.com)
  • In patients with non-operable CTEPH or persistent/recurrent PH after PEA, there is evidence for benefit from pulmonary vasodilator drug treatment. (wikipedia.org)
  • They can also be used to describe areas or effects where blood flow and ventilation are not properly matched though both may be present to varying extents. (wikipedia.org)
  • In all dogs, embolization caused an increase in blood flow and ventilation to VA/Q ratios less than 1. (ahajournals.org)
  • By redirecting blood flow from poorly-ventilated lung regions to well-ventilated lung regions, HPV is thought to be the primary mechanism underlying ventilation/perfusion matching. (wikipedia.org)
  • Moreover, a similar understanding exists for the relationship between the distribution of blood flow and the distribution of ventilation. (wikipedia.org)
  • The acquired data are then postprocessed to obtain perfusion maps with different parameters, such as BV (blood volume), BF (blood flow), MTT (mean transit time) and TTP (time to peak). (wikipedia.org)