Distribution of ventilation

Figure 2 Ascribed probability distribution of ventilation rate (Q).

Figure 2 shows the attributed distribution for the ventilation rate expressed in air changes per hour (ACH) as a uniform (i.e., totally random) distribution from 0.2 to 30 air changes per hour. In a room 3 m x 3 m X 2 m (18 m ) this is a uniform distribution of ventilation rate expressed in m h of Q = 3.6 to 540 m h That is, a distribution in which there is an equal probability of any values within this range occurring and a zero probability of any value occurring outside this range. 

Distribution of ventilation Single and multiple breath nitrogen washout Homogeneity of ventilation in lungs - airflow obstruction and gas trapping causes greater variability of ventilation... 

At least two regions of the respiratory tract are ventilated at different rates. Of the total inspired air, 40% ventilates 17% of the lung, and the remaining 60% ventilates the other 83% of the lung. As a consequence of such unequal distribution of ventilation, air velocity and times of air passage vary, producing different probabilities of deposition of the inhaled particles from one site to another at the same structural depth. 

Biological Samples. Multiple gas equilibration has been used to measure up to 8 foreign inert gases in blood, plasma, and dextrose solutions (11). The method is used to measure distributions of ventilation-perfusion ratios based upon the simultaneous preliminary clearance of several inert gases (28). It is well suited to monitoring anesthetics and trace blood levels of anesthetic agents. 

Distributions of Ventilation-Perfusion Ratios Theory, J. Appl. Physiol. 1974,36, 588-599. 

Distribution of ventilation is likely to be more uneven in the very young and the elderly due to the diminished elastic recoil from the chest wall and lung tissue respectively. 

Cooper DM, Mellins RB, Mansell AL. Changes in distribution of ventilation with lung growth. J Appl Physiol 1981 51 699-705. 

MRI with h3 perpolarized He has demonstrated the ability to identify and quantify impaired distribution of ventilation in lung transplant patients, in whom preferential distribution of the graft is observed (70). In patients with emphysema, patterns of irregular and delayed He entry with redistribution and air trapping were observed. This abnormal movement was not noted in healthy patients (71-73). 

Gast KK, Puderbach MU, Rodriguez I et al. Distribution of ventilation in lung transplant recipients evaluation by dynamic He-MRI with lung motion correction. Invest Radiol 2003 38 341-348. 

Porra L, Monfraix S, Berruyer G, Le Due G, Nemoz C, Thomlinson W, Suortti P, Sovijarvi AR, Bayat S. Effect of tidal volume on distribution of ventilation assessed by synchrotron radiation CT in rabbit. J Appl Physiol 2004 96(5) 1899-1908. 

Cylindrical vortex generator with the central input of a stream within the limits of at z = 0 represents nozzles. It he has found application for catching drops and distributions of ventilating air in premises rooms (Anthony, 1970). 

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