Flow and Volume Dependence of Rat Airway Resistance During Constant Flow Inflation and Deflation

Rubini, Alessandro; Carniel, Emanuele Luigi; Parmagnani, Andrea; Natali, Arturo N.

doi:10.1007/s00408-011-9318-z

Cited by 16 publications

(11 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The global resistances and compliances identified in this study agreed well with previously published data, 21,42,49 despite the limited experimental data available in this current study (Table 4). While the previous studies reported higher compliance values, the relative increase in compliance between emphysematous and healthy rats was similar.…”

Section: Discussionsupporting

confidence: 92%

“…Resistance during exhalation was set to 1.5 times the resistance during inhalation following previous work. 42 Once the R and C parameters were found for each rat, the volume and flow rate throughout the full breathing cycle were numerically calculated by solving equation 2. The average and standard deviation in each rat category were calculated for the maximum pressure, resistance, compliance, maximum flow rates during inhalation and exhalation.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Airflow and Particle Deposition Simulations in Health and Emphysema: From In Vivo to In Silico Animal Experiments

et al. 2013

View full text Add to dashboard Cite

Image-based in-silico modeling tools provide detailed velocity and particle deposition data. However, care must be taken when prescribing boundary conditions to model lung physiology in health or disease, such as in emphysema. In this study, the respiratory resistance and compliance were obtained by solving an inverse problem; a 0D global model based on healthy and emphysematous rat experimental data. Multi-scale CFD simulations were performed by solving the 3D Navier Stokes equations in an MRI-derived rat geometry coupled to a 0D model. Particles with 0.95 μm diameter were tracked and their distribution in the lung was assessed. Seven 3D-0D simulations were performed: healthy, homogeneous, and five heterogeneous emphysema cases. Compliance (C) was significantly higher (p = 0.04) in the emphysematous rats (C=0.37±0.14cm3cmH2O) compared to the healthy rats (C=0.25±0.04cm3cmH2O), while the resistance remained unchanged (p=0.83). There were increases in airflow, particle deposition in the 3D model, and particle delivery to the diseased regions for the heterogeneous cases compared to the homogeneous cases. The results highlight the importance of multi-scale numerical simulations to study airflow and particle distribution in healthy and diseased lungs. The effect of particle size and gravity were studied. Once available, these in-silico predictions may be compared to experimental deposition data.

show abstract

Section: Discussionsupporting

confidence: 92%

Section: Methodsmentioning

confidence: 99%

Airflow and Particle Deposition Simulations in Health and Emphysema: From In Vivo to In Silico Animal Experiments

et al. 2013

View full text Add to dashboard Cite

show abstract

“…The mean heart rate values reported here are similar to those expected in normal rats under general anesthesia [28]. As expected, body temperature increments caused a related increase in heart rate [9], which could have increased pulmonary blood flow, which is known to affect lung mechanics [29].…”

Section: Discussionsupporting

confidence: 87%

The effect of body temperature on the dynamic respiratory system compliance–breathing frequency relationship in the rat

Rubini

Bosco

2013

J Biol Phys

Self Cite

View full text Add to dashboard Cite

The mechanical inhomogeneity of the respiratory system is frequently investigated by measuring the frequency dependence of dynamic compliance, but no data are currently available describing the effects of body temperature variations. The aim of the present report was to study those effects in vivo. Peak airway pressure was measured during positive pressure ventilation in eight anesthetized rats while breathing frequency (but not tidal volume) was altered. Dynamic compliance was calculated as the tidal volume/peak airway pressure, and measurements were taken in basal conditions (mean rectal temperature 37.3 °C) as well as after total body warming (mean rectal temperature 39.7 °C). Due to parenchymal mechanical inhomogeneity and stress relaxation-linked effects, the normal rat respiratory system exhibited frequency dependence of dynamic lung compliance. Even moderate body temperature increments significantly reduced the decrements in dynamic compliance linked to breathing rate increments. The results were analyzed using Student's and Wilcoxon's tests, which yielded the same results (p < 0.05). Body temperature variations are known to influence respiratory mechanics. The frequency dependence of dynamic compliance was found, in the experiments described, to be temperature-dependent as temperature variations affected parenchymal mechanical inhomogeneity and stress relaxation. These results suggest that body temperature variations should be taken into consideration when the dynamic compliance-breathing frequency relationship is being examined during clinical assessment of inhomogeneity of lung parenchyma in patients.

show abstract

“…their relaxation times are the same. Following our previous work [22], the 0D resistance during expiration was set to 1.5 times the 0D resistance during inhalation ( R i , j ex = 1.5 R i , j ) [26]. …”

Section: Methodsmentioning

confidence: 99%

Distribution of aerosolized particles in healthy and emphysematous rat lungs: Comparison between experimental and numerical studies

Oakes

Marsden

Grandmont

et al. 2015

Journal of Biomechanics

View full text Add to dashboard Cite

In silico models of airflow and particle deposition in the lungs are increasingly used to determine the therapeutic or toxic effects of inhaled aerosols. While computational methods have advanced significantly, relatively few studies have directly compared model predictions to experimental data. Furthermore, few prior studies have examined the influence of emphysema on particle deposition. In this work we performed airflow and particle simulations to compare numerical predictions to data from our previous aerosol exposure experiments. Employing an image-based 3D rat airway geometry, we first compared steady flow simulations to coupled 3D-0D unsteady simulations in the healthy rat lung. Then, in 3D-0D simulations, the influence of emphysema was investigated by matching disease location to the experimental study. In both the healthy unsteady and steady simulations, good agreement was found between numerical predictions of aerosol delivery and experimental deposition data. However, deposition patterns in the 3D geometry differed between the unsteady and steady cases. On the contrary, satisfactory agreement was not found between the numerical predictions and experimental data for the emphysematous lungs. This indicates that the deposition rate downstream of the 3D geometry is likely proportional to airflow delivery in the healthy lungs, but not in the emphysematous lungs. Including small airway collapse, variations in downstream airway size and tissue properties, and tracking particles throughout expiration may result in a more favorable agreement in future studies.

show abstract

Flow and Volume Dependence of Rat Airway Resistance During Constant Flow Inflation and Deflation

Cited by 16 publications

References 33 publications

Airflow and Particle Deposition Simulations in Health and Emphysema: From In Vivo to In Silico Animal Experiments

Airflow and Particle Deposition Simulations in Health and Emphysema: From In Vivo to In Silico Animal Experiments

The effect of body temperature on the dynamic respiratory system compliance–breathing frequency relationship in the rat

Distribution of aerosolized particles in healthy and emphysematous rat lungs: Comparison between experimental and numerical studies

Contact Info

Product

Resources

About