Disease relevance of Ventilation-Perfusion Ratio

• Prostacyclin nebulization is an excellent tool to reduce pulmonary hypertension and to improve the ventilation/perfusion ratio [1].
• Almitrine, a peripheral chemoreceptor stimulating drug, was given 100 mg orally to six patients with advanced chronic obstructive pulmonary disease (COPD), and its effects on hemodynamics, blood gases, lung mechanics, and the distribution of ventilation/perfusion ratios (VA/Q), determined by the inert gas elimination technique, were investigated [2].
• Distributions of ventilation-perfusion ratios (VA/Q) were determined, using the multiple inert gas elimination technique, at baseline, during hypoxia, and again during hypoxia after nifedipine intake [3].
• The more rapid increase in PACO2 above thetaLa- was consistent with an accelerated CO2 exchange, whereas the more rapid rate of change in PAO2 in 3 of the subjects may have reflected the development of an increased distribution of the ventilation perfusion ratio in addition to the effects of hyperventilation [4].
• To determine and to quantify the pulmonary and extrapulmonary contributors to hypoxemia in liver cirrhosis, we measured in 10 cirrhotics blood gases, P50, hemodynamics, ventilation, and the distribution of ventilation-perfusion ratios (VA/Q) using the multiple inert gas elimination technique [5].

Psychiatry related information on Ventilation-Perfusion Ratio

• Conversely alveolar efficiency for CO2, obtained with the nitrogen wash-out test, in the supine posture increased from 81.7 to 90.5%, indicating an improvement in ventilation/perfusion ratio as a possible determinant of blood gas tension improvement during wakefulness and, as a consequence, also during sleep [6].

High impact information on Ventilation-Perfusion Ratio

• During periods of reduced O2 availability, three major mechanisms act conjointly to increase ventilation and optimize the ventilation-perfusion ratio throughout the lung by directing pulmonary blood flow to better ventilated areas of the lung [7].
• Ventilation/perfusion ratios and simultaneous dual-radionuclide single-photon emission tomography with krypton-81m and technetium-99m macroaggregated albumin [8].
• The poor results obtained with CO2 elimination can be explained by its dependence on the ventilation-perfusion ratio and the effect of oxygen tension on the CO2 binding capacity of blood (Haldane effect) [9].
• The effects of intravenous pentobarbital versus nitrous oxide/halothane inhalation anesthesia on blood gases, distribution of ventilation-perfusion ratios (VA/Q), and lung volume (FRC) were compared in 8 tracheostomized sheep in the lateral decubitus position [10].
• During sevoflurane and isoflurane anesthesia, blood flow to lung areas with a low ventilation/perfusion ratio (Va/Q) was significantly increased in comparison with control [11].

Chemical compound and disease context of Ventilation-Perfusion Ratio

• Hemodynamics, blood gases, lung mechanics, and the distributions of ventilation-perfusion ratios (VA/Q) were studied before and after iv diltiazem, 0.5 mg/kg over 30 min, in 6 patients with pulmonary hypertension secondary to the adult respiratory distress syndrome (ARDS) ventilated with 7 to 20 cm H2O positive end-expiratory pressure (PEEP) [12].

Biological context of Ventilation-Perfusion Ratio

• It is concluded that felodipine lowers pulmonary vascular resistance but at the expense of a worsening of the ventilation-perfusion ratio [13].
• The ventilation-perfusion ratios were determined from xenon-133 ventilation studies and 99-tc-m-labeled particle perfusion scans, using either the fractional exchange of air or the relative distribution of tidal volume per unit volume as the numerator of the ratio [14].

Associations of Ventilation-Perfusion Ratio with chemical compounds

• The method enables determination of the distribution of ventilation-perfusion ratios in the lungs during anesthesia with nitrous oxide and halothane [15].
• The lack of significant change in ventilation and the decrease in the alveolar-arterial oxygen gradient (mean decrease -10.0 +/- 1.9 mm Hg; p less than 0.001) at rest suggests a change in the distribution of the ventilation-perfusion ratio in the lung; such a change was confirmed by a krypton 81m isotopic study [16].
• The improvement of arterial oxygen saturation by pretreatment with L-arginine could be ascribed to an enhancement of the ventilation/perfusion ratio [17].
• Measurement of the CO diffusion capacity indicates more effective gas diffusion and a better ventilation-perfusion ratio for at least 11 h, especially after inhalation of 24 micrograms formoterol [18].
• Physiological and anatomical shunts were increased with PGE1 (20.2% and 14.8%) and the overall ventilation/perfusion ratio decreased from 0.89 to 0.79 [19].

Gene context of Ventilation-Perfusion Ratio

• In patients with VSD with PAB the severe abnormality of ventilation-perfusion ratio returned toward normal after corrective operation but did not reach normal [20].
• With respect to other beta 2-adrenoceptor agonists, this compound did not appear to increase minute ventilation or to induce an impairment of ventilation/perfusion ratio, at least after 20 min, when the bronchodilation was still evident [21].

Analytical, diagnostic and therapeutic context of Ventilation-Perfusion Ratio

• The combined use of transmission and emission imaging provides quantitative information about regional lung structure (density, extravascular density, and vascular volume) and function (ventilation, perfusion, ventilation-perfusion ratios, glucose metabolic rate) [22].

References