Regional deposition of inhaled particles in human lungs: comparison between men and women

1998 ◽  
Vol 84 (6) ◽  
pp. 1834-1844 ◽  
Author(s):  
Chong S. Kim ◽  
S. C. Hu
Keyword(s):  
Particle Deposition ◽  
Fine Particles ◽  
Particle Diameter ◽  
Flow Rates ◽  
Men And Women ◽  
Inhaled Particles ◽  
Regional Deposition ◽  
Delivery Technique ◽  
Deposition Fraction ◽  
The Difference

We measured detailed regional deposition patterns of inhaled particles in healthy adult male ( n = 11; 25 ± 4 yr of age) and female ( n = 11; 25 ± 3 yr of age) subjects by means of a serial bolus aerosol delivery technique for monodisperse fine [particle diameter ( D p) = 1 μm] and coarse aerosols ( D p = 3 and 5 μm). The bolus aerosol (40 ml half-width) was delivered to a specific volumetric depth (Vp) of the lung ranging from 100 to 500 ml with a 50-ml increment, and local deposition fraction (LDF) was assessed for each of the 10 local volumetric regions. In all subjects, the deposition distribution pattern was very uneven with respect to Vp, showing characteristic unimodal curves with respect to particle size and flow rate. However, the unevenness was more pronounced in women. LDF tended to be greater in all regions of the lung in women than in men for D p = 1 μm. For D p = 3 and 5 μm, LDF showed a marked enhancement in the shallow region of Vp ≤ 200 ml in women compared with men ( P < 0.05). LDF in women was comparable to or smaller than those of men in deep lung regions of Vp > 200 ml. Total lung deposition was comparable between men and women for fine particles but was consistently greater in women than men for coarse particles regardless of flow rates used: the difference ranged from 9 to 31% and was greater with higher flow rates ( P < 0.05). The results indicate that 1) particle deposition characteristics differ between healthy men and women under controlled breathing conditions and 2) deposition in women is greater than that in men.

Assessment of regional deposition of inhaled particles in human lungs by serial bolus delivery method

1996 ◽  
Vol 81 (5) ◽  
pp. 2203-2213 ◽  
Author(s):  
Chong S. Kim ◽  
S. C. Hu ◽  
P. Dewitt ◽  
T. R. Gerrity
Keyword(s):  
Particle Diameter ◽  
Deposition Efficiency ◽  
Dead Volume ◽  
Delivery Method ◽  
Constant Flow Rate ◽  
Inhaled Particles ◽  
Human Lungs ◽  
Regional Deposition ◽  
Delivery Technique ◽  
Deposition Fraction

Kim, Chong S., S. C. Hu, P. DeWitt, and T. R. Gerrity.Assessment of regional deposition of inhaled particles in human lungs by serial bolus delivery method. J. Appl. Physiol. 81(5): 2203–2213, 1996.—Detailed regional deposition of inhaled particles was investigated in young adults ( n = 11) by use of a serial bolus aerosol delivery technique. A small bolus (45 ml half-width) of monodisperse aerosols [1-, 3-, and 5-μm particle diameter ( D p)] was delivered sequentially to a specific volumetric depth of the lung (100–500 ml in 50-ml increments), while the subject inhaled clean air via a laser aerosol photometer (25-ml dead volume) with a constant flow rate (Q˙ = 150, 250, and 500 ml/s) and exhaled with the same Q˙ without a pause to the residual volume. Deposition efficiency (LDE) and deposition fraction in 10 local volumetric regions and total deposition fraction of the lung were obtained. LDE increased monotonically with increasing lung depth for all three D p. LDE was greater with smaller Q˙ values in all lung regions. Deposition was distributed fairly evenly throughout the lung regions with a tendency for an enhancement in the distal lung regions for D p = 1 μm. Deposition distribution was highly uneven for D p = 3 and 5 μm, and the region of the peak deposition shifted toward the proximal regions with increasing D p. Surface dose was 1–5 times greater in the small airway regions and 2–17 times greater in the large airway regions than in the alveolar regions. The results suggest that local or regional enhancement of deposition occurs in healthy subjects and that the local enhancement can be an important factor in health risk assessment of inhaled particles.

scholarly journals Increase in relative deposition of fine particles in the rat lung periphery in the absence of gravity

2014 ◽  
Vol 117 (8) ◽  
pp. 880-886 ◽  
Author(s):  
Chantal Darquenne ◽  
Maria G. Borja ◽  
Jessica M. Oakes ◽  
Ellen C. Breen ◽  
I. Mark Olfert ◽  
...  
Keyword(s):  
Particle Deposition ◽  
Fine Particles ◽  
Left Lung ◽  
Retention Rates ◽  
Inhaled Particles ◽  
Regional Deposition ◽  
Research Aircraft ◽  
The Difference ◽  
Magnetic Resonance Imaging Mri ◽  
Lung Periphery

While it is well recognized that pulmonary deposition of inhaled particles is lowered in microgravity (μG) compared with gravity on the ground (1G), the absence of sedimentation causes fine particles to penetrate deeper in the lung in μG. Using quantitative magnetic resonance imaging (MRI), we determined the effect of gravity on peripheral deposition (DEPperipheral) of fine particles. Aerosolized 0.95-μm-diameter ferric oxide particles were delivered to spontaneously breathing rats placed in plethysmographic chambers both in μG aboard the NASA Microgravity Research Aircraft and at 1G. Following exposure, lungs were perfusion fixed, fluid filled, and imaged in a 3T MR scanner. The MR signal decay rate, R2*, was measured in each voxel of the left lung from which particle deposition (DEP) was determined based on a calibration curve. Regional deposition was assessed by comparing DEP between the outer (DEPperipheral) and inner (DEPcentral) areas on each slice, and expressed as the central-to-peripheral ratio. Total lung deposition tended to be lower in μG compared with 1G (1.01 ± 0.52 vs. 1.43 ± 0.52 μg/ml, P = 0.1). In μG, DEPperipheral was larger than DEPcentral ( P < 0.03), while, in 1G, DEPperipheral was not significantly different from DEPcentral. Finally, central-to-peripheral ratio was significantly less in μG than in 1G ( P ≤ 0.05). These data show a larger fraction of fine particles depositing peripherally in μG than in 1G, likely beyond the large- and medium-sized airways. Although not measured, the difference in the spatial distribution of deposited particles between μG and 1G could also affect particle retention rates, with an increase in retention for particles deposited more peripherally.

Factors Influencing the Regional Deposition of Inhaled Particles in Man

1983 ◽  
Vol 64 (1) ◽  
pp. 69-78 ◽  
Author(s):  
M. J. Chamberlain ◽  
W. K. C. Morgan ◽  
S. Vinitski
Keyword(s):  
Regional Differences ◽  
Particle Deposition ◽  
Normal Subjects ◽  
Radioactive Aerosol ◽  
Breathing Rate ◽  
Regional Ventilation ◽  
Inhaled Particles ◽  
Human Lungs ◽  
Regional Deposition ◽  
Normal Human

1. Although ventilation in normal human lungs has been shown to decrease from apex to base, comparable observations are lacking in regard to particle deposition. 2. We compared regional ventilation and particle deposition in normal subjects by using radioactive xenon and a radioactive aerosol while sitting, lying, and while breathing at an increased rate. Both smokers and non-smokers were studied. 3. Particle deposition and ventilation were closely related, and the greater the ventilation the greater the deposition of particles, a situation which prevailed irrespective of position and breathing rate. While supine, the apex to base gradient for both ventilation and particle deposition decreased but did not entirely disappear. At higher respiratory rates, central deposition of particles, especially in smokers, increased. 4. We concluded that there are regional differences in the deposition of particles and that such differences are closely related to regional ventilation.

Quantitative deposition of ultrafine stable particles in the human respiratory tract

1985 ◽  
Vol 58 (1) ◽  
pp. 223-229 ◽  
Author(s):  
F. J. Wilson ◽  
F. C. Hiller ◽  
J. D. Wilson ◽  
R. C. Bone
Keyword(s):  
Respiratory Tract ◽  
Particle Deposition ◽  
Theoretical Models ◽  
Respiratory Pattern ◽  
Normal Male ◽  
Human Respiratory Tract ◽  
Size Fractions ◽  
Inhaled Particles ◽  
The Difference ◽  
Stable Particles

Theoretical models of particle deposition in the respiratory tract predict high fractional deposition for particles of less than 0.1 micron, but there are few confirming experimental data for those predictions. We have measured the deposition fraction of a nonhygroscopic aerosol in the human respiratory tract. The aerosol had a count mean diameter of 0.044 micron SD of 1.93, as measured with an electrical aerosol analyzer, and was produced from a 0.01% solution of bis(2-ethylhexyl) sebacate using a condensation generator. Subjects inhaled the aerosol using a controlled respiratory pattern of 1 liter tidal volume, 12/min. Deposition was calculated as the difference in concentration between inhaled and exhaled aerosol of five size fractions corrected for system deposition and dead-space constants. Three deposition studies were done on each of five normal male volunteers. Means (+/- SE) for the five size fractions were 0.024 micron, 0.71 +/- 0.06; 0.043 micron, 0.62 +/- 0.06; 0.075 micron, 0.53 +/- 0.05; 0.13 micron, 0.44 +/- 0.04; and 0.24 micron, 0.37 +/- 0.06. These data demonstrate that deposition of inhaled particles in the 0.024- to 0.24-micron size range is high and increases with decreasing size. These observations agree with and validate predictions of mathematical models.

Role of Alveolar Topology on Acinar Flows and Convective Mixing

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Philipp Hofemeier ◽  
Josué Sznitman
Keyword(s):  
Particle Deposition ◽  
Fine Particles ◽  
Flow Patterns ◽  
Local Flow ◽  
Convective Mixing ◽  
Pulmonary Acinus ◽  
Inhaled Particles ◽  
Flow Mixing ◽  
Passive Tracers

Due to experimental challenges, computational simulations are often sought to quantify inhaled aerosol transport in the pulmonary acinus. Commonly, these are performed using generic alveolar topologies, including spheres, toroids, and polyhedra, to mimic the complex acinar morphology. Yet, local acinar flows and ensuing particle transport are anticipated to be influenced by the specific morphological structures. We have assessed a range of acinar models under self-similar breathing conditions with respect to alveolar flow patterns, convective flow mixing, and deposition of fine particles (1.3 μm diameter). By tracking passive tracers over cumulative breathing cycles, we find that irreversible flow mixing correlates with the location and strength of the recirculating vortex inside the cavity. Such effects are strongest in proximal acinar generations where the ratio of alveolar to ductal flow rates is low and interalveolar disparities are most apparent. Our results for multi-alveolated acinar ducts highlight that fine 1 μm inhaled particles subject to alveolar flows are sensitive to the alveolar topology, underlining interalveolar disparities in particle deposition patterns. Despite the simplicity of the acinar models investigated, our findings suggest that alveolar topologies influence more significantly local flow patterns and deposition sites of fine particles for upper generations emphasizing the importance of the selected acinar model. In distal acinar generations, however, the alveolar geometry primarily needs to mimic the space-filling alveolar arrangement dictated by lung morphology.

Influence of aeration and permeate flux on deposition of particulates on membrane surface

2010 ◽  
Vol 10 (6) ◽  
pp. 979-986
Author(s):  
Rupak Aryal ◽  
Saravanamuthu Vigneswaran ◽  
Jaya Kandasamy ◽  
Bivek Baral ◽  
Alain Grasmick
Keyword(s):  
Particle Deposition ◽  
Membrane Surface ◽  
Particle Diameter ◽  
Transmembrane Pressure ◽  
Physical Parameters ◽  
Permeate Flux ◽  
Composite Effect ◽  
Maximum Particle ◽  
The Difference ◽  
Two Parameters

In microfiltration, a deposit of foulant tends to form on the membrane surface and this usually controls the performance of the filtration process. This paper discusses the influence of physical parameters such as aeration and permeates flux on migration and deposition of above micron particles on the membrane surface. Kaolin clay suspension of particle 3.7–8 μm with mean particle diameter 4.1 μm was used in this study. Equal amount of mass of deposited particles on the membrane surface created different transmembrane pressure (TMP) when operated at different aeration rates and permeate flux showing that there is a composite effect. The particle deposition rate at the beginning at lower flux was almost linear which changed to a sharp logarithamic rise at higher flux. The difference in TMP rise for the same amount of deposit demonstrated the selective nature of particle deposition. The mass of the particle deposition on the membrane surface could be described by two parameters: maximum deposition and time using a simple empirical logarithamic equation y=k/[1+exp(b−at)], where k, a, and b are constant; y is the particulate mass deposit (g/m2) and t is the time. The maximum particle mass deposition growth could be described by the equation dy/dt=1/4ka.

Comparative numerical simulation of inhaled particle dispersion in upper human airway to analyse intersubject differences

2020 ◽  
Vol 29 (6) ◽  
pp. 793-809
Author(s):  
Nguyen Lu Phuong ◽  
Nguyen Dang Khoa ◽  
Kazuhide Ito
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Surface Pressure ◽  
Particle Deposition ◽  
Nasal Passage ◽  
Upper Airways ◽  
Flow Rates ◽  
Total Deposition ◽  
Deposition Fraction ◽  
Wall Shear

This study predicted the total and regional deposition of particles in realistic upper human airways and demonstrated the effects of intersubject variations in deposition fraction. Two airway models were studied under flow rates ranging from 0.45 to 2.4 m3/h and particle aerodynamic diameters from 1 to 10 μm. The total deposition predictions were validated using in vivo and in vitro experimental data. The intricate airway structures generated heterogeneities of airflow distributions and corresponding particle dispersions and depositions in the models. Nevertheless, with modified inertial parameters, the total deposition fraction curves of the two human upper airway models, as functions of flow rates, converged to a single function. However, regional particle deposition fractions differed significantly among the two models. The surface pressure and wall-shear stress distribution were investigated to assess the relationship of surface pressure and wall-shear stress with hotspot locations in upper airways of both models. For one subject (model A), the central nasal passage regions were found to be sites of higher deposition over the range of particle sizes and flow rates targeted in this study. For the other subject (model B), higher deposition was mostly observed in the vestibule region, caused due to particle inertia as the airway consisted of curvatures. The accelerated flow regions acted as a natural filter to high inertial particles. The results indicated that both total and regional depositions exhibited significant intersubject differences.

Human variation in the peripheral air-space deposition of inhaled particles

1987 ◽  
Vol 62 (4) ◽  
pp. 1603-1610 ◽  
Author(s):  
W. D. Bennett ◽  
G. C. Smaldone
Keyword(s):  
Particle Deposition ◽  
Hold Time ◽  
Normal Subjects ◽  
Breath Hold ◽  
Inhaled Particles ◽  
Space Size ◽  
Air Space ◽  
Deposition Fraction ◽  
Lung Periphery ◽  
Conducting Airways

Intersubject variability in both peripheral air-space dimensions and breathing pattern [tidal volume (VT) and respiratory frequency (f)] may play a role in determining intersubject variation in the fractional deposition of inhaled particles that primarily deposit in the lung periphery (i.e., distal to conducting airways). In healthy subjects breathing spontaneously at rest, we measured the deposition fraction (DF) of a 2.6-microns monodisperse aerosol by Tyndallometry while simultaneous measurement of VT and f were made. Under these conditions particle deposition occurs primarily in the peripheral air spaces of the lung. As an index of peripheral air-space size, we used measurements of aerosol recovery (RC) as a function of breath-hold time (t) (Gebhart et al. J. Appl. Physiol. 51: 465–476, 1981). In each subject, we measured RC (aerosol expired/aerosol inspired) of a 1.0-micron monodisperse aerosol as a function of breath-hold time for inspiratory capacity breaths of aerosol. The half time (t1/2) (the breath-hold time to reach 50% RC with no breath hold) is proportional to a mean diameter (D) of air spaces filled with aerosol. In the 10 subjects studied, we found a variable DF, range 0.04–0.44 [0.25 +/- 0.12 (SD)]. DF correlated most closely with 1/f, or the period of breathing (r = 0.96, P less than 0.01). There was no significant correlation between DF and t1/2 as an index of peripheral air-space size. In fact there was little deviation in t1/2 in these normal subjects [coefficient of variation (CV) = 0.12].(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of exercise on deposition and subsequent retention of inhaled particles

1985 ◽  
Vol 59 (4) ◽  
pp. 1046-1054 ◽  
Author(s):  
W. D. Bennett ◽  
M. S. Messina ◽  
G. C. Smaldone
Keyword(s):  
Particle Deposition ◽  
Human Subjects ◽  
Regional Distribution ◽  
Bicycle Ergometer ◽  
Inhaled Particles ◽  
Significant Difference ◽  
Lung Retention ◽  
Deposition Fraction ◽  
Normal Human ◽  
Rest And Exercise

To investigate the effect of exercise and its associated increase in ventilation on the deposition and subsequent retention of inhaled particles, we measured the fractional and regional lung deposition of a radioactively tagged (99mTc) monodisperse aerosol (2.6 microns mass median aerodynamic diam) in normal human subjects at rest and while exercising on a bicycle ergometer. Breath-by-breath deposition fraction (DF) was measured throughout the aerosol exposures by Tyndallometry. Following each exposure gamma camera analysis was used to 1) determine the regional distribution of deposited particles and 2) monitor lung retention for 2.5 h and again at 24 h. We found that DF was unchanged between ventilation at rest (6–10 l/min) and exercise (32–46 l/min). Even though mouth deposition was enhanced with exercise, it was not large enough to produce a significant difference in the deposition fraction of the lung (DFL) between resting and exercise exposures. The central-to-peripheral distribution of deposited aerosol was larger for the exercise vs. resting exposure, reflecting a shift of particle deposition to more central bronchial airways. Apical-to-basal distribution was not different for the two exposures. Retention at 2.5 h and 24 h (R24) was reduced following the exercise vs. the resting exposure, consistent with greater bronchial deposition during exercise. The product of DFL and R24 gave a measure of fractional burden at 24 h (B24), i.e., the fraction of inhaled aerosol residing in the lungs 24 h after exposure. B24 was not significantly different between rest and exercise exposures.

scholarly journals Comparison of Two Models to Estimate Deposition of Fungi and Bacteria in the Human Respiratory Tract

Atmosphere ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 561
Author(s):  
Jessica A. Sagona ◽  
Lynn E. Secondo ◽  
Gediminas Mainelis
Keyword(s):  
Particle Deposition ◽  
Computational Models ◽  
Mouth Breathing ◽  
Human Respiratory Tract ◽  
Alveolar Region ◽  
Multiple Path ◽  
Total Deposition ◽  
Deposition Fraction ◽  
Path Models ◽  
The Difference

Understanding the deposition of bioaerosols in the respiratory system may help determine the risk of disease; however, measuring deposition fraction in-situ is difficult. Computational models provide estimates of particle deposition fraction for given breathing and particle parameters; however, these models traditionally have not focused on bioaerosols. We calculated deposition fractions in an average-sized adult with a new bioaerosol-specific lung deposition model, BAIL, and with two multiple-path models for three different breathing scenarios: “default” (subject sitting upright and breathing nasally), “light exercise”, and “mouth breathing”. Within each scenario, breathing parameters and bioaerosol characteristics were kept the same across all three models. BAIL generally calculated a higher deposition fraction in the extrathoracic (ET) region and a lower deposition fraction in the alveolar region than the multiple-path models. Deposition fractions in the tracheobronchial region were similar among the three models; total deposition fraction patterns tended to be driven by the ET deposition fraction, with BAIL resulting in higher deposition in some scenarios. The difference between deposition fractions calculated by BAIL and other models depended on particle size, with BAIL generally indicating lower total deposition for bacteria-sized bioaerosols. We conclude that BAIL predicts somewhat lower deposition and, potentially, reduced risk of illness from smaller bioaerosols that cause illness due to deposition in the alveolar region. On the other hand, it suggests higher deposition in the ET region, especially for light exercise and mouth-breathing scenarios. Additional comparisons between the models for other breathing scenarios, people’s age, and different bioaerosol particles will help improve our understanding of bioaerosol deposition.

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