Optimal Determination of Respiratory Airflow Patterns for a General Multicompartment Lung Mechanics System With Nonlinear Resistance and Compliance Parameters

2015 ◽  
Vol 137 (12) ◽  
Author(s):  
Saing Paul Hou ◽  
Nader Meskin ◽  
Wassim M. Haddad
Keyword(s):  
Optimization Criterion ◽  
Lung Model ◽  
Lung Mechanics ◽  
Type Model ◽  
Airflow Rate ◽  
Mechanics Model ◽  
Respiratory Airflow ◽  
Elastic Potential Energy ◽  
And Function ◽  
Nonlinear Resistance

In this paper, we develop a framework for determining optimal respiratory airflow patterns for a multicompartment lung mechanics system with nonlinear resistance and compliance parameters. First, a nonlinear multicompartment lung mechanics model that accounts for nonlinearities in both the airway resistances and the lung compliances is developed. In particular, we assume that the resistive losses are characterized by a Rohrer-type model with resistive losses defined as the sum of linear and quadratic terms of the airflow. The proposed model is more realistic than those presented in the literature, since it takes into account the heterogeneity of lung anatomy and function as well as the nonlinearity of lung resistance and compliance parameters. This model can be used to provide a better understanding of pulmonary function as well as the process of mechanical ventilation. Next, using the proposed nonlinear multicompartment lung model, we develop a framework for determining optimal respiratory airflow patterns. Specifically, an optimization criterion that involves the minimization of the oxygen consumption of the lung muscles and lung volume acceleration for the inspiratory phase, and the minimization of the elastic potential energy and rapid airflow rate changes for the expiratory phase is formulated and solved. The solution to the formulated optimization problem is derived using classical calculus of variation techniques. Finally, several illustrative numerical examples are presented to illustrate the efficacy of the proposed nonlinear multicompartment lung model and the corresponding optimal airflow patterns. Comparison with experimental data shows that our nonlinear resistance model predicts the airflow patterns more accurately than linear resistance models. Moreover, the optimization criterion used in this paper also provides a more accurate prediction of the optimal airflow patterns.

scholarly journals Optimal Determination of Respiratory Airflow Patterns Using a Nonlinear Multicompartment Model for a Lung Mechanics System

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Hancao Li ◽  
Wassim M. Haddad
Keyword(s):  
Work Of Breathing ◽  
Optimality Criteria ◽  
Lung Mechanics ◽  
Airflow Rate ◽  
Multicompartment Model ◽  
Classical Calculus ◽  
Inspiratory Phase ◽  
Respiratory Airflow ◽  
Elastic Potential Energy

We develop optimal respiratory airflow patterns using a nonlinear multicompartment model for a lung mechanics system. Specifically, we use classical calculus of variations minimization techniques to derive an optimal airflow pattern for inspiratory and expiratory breathing cycles. The physiological interpretation of the optimality criteria used involves the minimization of work of breathing and lung volume acceleration for the inspiratory phase, and the minimization of the elastic potential energy and rapid airflow rate changes for the expiratory phase. Finally, we numerically integrate the resulting nonlinear two-point boundary value problems to determine the optimal airflow patterns over the inspiratory and expiratory breathing cycles.

Simple point of care continuous positive airway pressure delivery device (Jain-CPAP)

2019 ◽  
Vol 5 (1) ◽  
pp. 13-19
Author(s):  
Ashish Jain ◽  
Robert M DiBlasi ◽  
Veena Devgan ◽  
Nisha Kumari ◽  
Kunal Kalra
Keyword(s):  
Continuous Positive Airway Pressure ◽  
Airway Pressure ◽  
Preterm Neonate ◽  
Positive Airway Pressure ◽  
Point Of Care ◽  
Healthcare Providers ◽  
Linear Increase ◽  
Lung Model ◽  
Lung Mechanics ◽  
Mean Pressure

ObjectiveTo describe the effective pressure and FiO2 delivery to a realistic spontaneously breathing lung model using a novel, simple, inexpensive neonatal non-invasive bubble continuous positive airway pressure (CPAP) device.MethodsThis experimental bench study was conducted at Bench Testing Laboratory at a Children’s Hospital. A realistic 3D anatomic airway model of a 28-week preterm neonate was affixed to the ASL5000 Test Lung to simulate spontaneous breathing with lung mechanics that are specific to a preterm neonate. The assembly was constructed on site using easily available nasal prongs, paediatric infusion set with a graduated chamber, three-way stop cocks and oxygen tubing. The adult nasal prong was used as cannulae. However, this assembly had the limitation of the lack of humidification and inability to deliver graduated oxygen. This assembly was attached to the anatomic airway with nasal prongs. Pressure and FiO2 were measured from within the lung model at different flow settings and recorded for 10 breaths.ResultsThere was a linear increase in the mean pressure in the 10 recorded breaths as oxygen flows were increased.ConclusionsOur nasal CPAP is a simple device, as it can be easily assembled at the point of care using simple, affordable supplies by the healthcare providers and can benefit the newborns with respiratory distress in the resource constraint settings.

Effect of respiratory airflow rate on removal of soluble vapors by the nose.

1974 ◽  
Vol 37 (5) ◽  
pp. 654-657 ◽  
Author(s):  
E F Aharonson ◽  
H Menkes ◽  
G Gurtner ◽  
D L Swift ◽  
D F Proctor
Keyword(s):  
Airflow Rate ◽  
Respiratory Airflow

scholarly journals Diversity, friction, and harmonisation: An ethnographic study of interprofessional teamwork dynamics

2021 ◽  
Author(s):  
Henriette Lund Skyberg
Keyword(s):  
Empirical Studies ◽  
Ethnographic Study ◽  
Type Model ◽  
Successful Implementation ◽  
Team Meetings ◽  
Interprofessional Teams ◽  
Interprofessional Teamwork ◽  
Use Context ◽  
And Function ◽  
Depth Interviews

Abstract Background: Although diversity, friction, and harmonisation in interprofessional teamwork are aspects frequently conceptualised, no empirical studies discuss them in combination. Focusing on risk and function with respect to each aspect, this paper examines how dynamics between these aspects during interprofessional teamwork interactions can foster (ideal) conditions for productive teamwork.Methods: An ethnographic study of three interprofessional teams in a mental health and substance use context in Norway, was conducted. Data were collected through observations of 14 team meetings and 18 in-depth interviews with health and social work professionals. Thematic analysis was applied to code the data.Results: A conceptual ideal-type model, which includes all three aspects, was developed to represent the emergent findings. The results suggest that the diversity of professional perspectives inherent in interprofessional teams is the foundation of interprofessional teamwork. However, friction is needed to promote innovation, encourage new insights, and intensify discussions. Harmonisation balances professional distinctions, fosters trust, and ties professionals together.Conclusion: This paper presents a comprehensive model of how professionals work together in interprofessional teams that makes visible the functions and risks of each aspect and the dynamics between them. Furthermore, it argues for mobilising all three aspects in combination during interprofessional teamwork to maximise productivity. Such insight can be used to support the development and successful implementation of interprofessional teamwork in health care.

scholarly journals Intrinsic Abnormalities of Cystic Fibrosis Airway Connective Tissue Revealed by an In Vitro 3D Stromal Model

Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1371
Author(s):  
Claudia Mazio ◽  
Laura S. Scognamiglio ◽  
Rossella De Cegli ◽  
Luis J. V. Galietta ◽  
Diego Di Bernardo ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Inflammatory Response ◽  
Bacterial Infections ◽  
Inflammatory Cells ◽  
Lung Model ◽  
Lung Dysfunction ◽  
Novel Therapeutic Strategies ◽  
And Function

Cystic fibrosis is characterized by lung dysfunction involving mucus hypersecretion, bacterial infections, and inflammatory response. Inflammation triggers pro-fibrotic signals that compromise lung structure and function. At present, several in vitro cystic fibrosis models have been developed to study epithelial dysfunction but none of these focuses on stromal alterations. Here we show a new cystic fibrosis 3D stromal lung model made up of primary fibroblasts embedded in their own extracellular matrix and investigate its morphological and transcriptomic features. Cystic fibrosis fibroblasts showed a high proliferation rate and produced an abundant and chaotic matrix with increased protein content and elastic modulus. More interesting, they had enhanced pro-fibrotic markers and genes involved in epithelial function and inflammatory response. In conclusion, our study reveals that cystic fibrosis fibroblasts maintain in vitro an activated pro-fibrotic state. This abnormality may play in vivo a role in the modulation of epithelial and inflammatory cell behavior and lung remodeling. We argue that the proposed bioengineered model may provide new insights on epithelial/stromal/inflammatory cells crosstalk in cystic fibrosis, paving the way for novel therapeutic strategies.

A statistical mechanics model for the collective epigenetic histone modification dynamics

2014 ◽  
Author(s):  
Hang Zhang ◽  
XIAO-JUN TIAN ◽  
Abhishek Mukhopadhyay ◽  
Kenneth S Kim ◽  
Jianhua Xing
Keyword(s):  
Histone Modifications ◽  
Nearest Neighbor ◽  
Covalent Modification ◽  
Type Model ◽  
Theoretical Studies ◽  
Lateral Interactions ◽  
Epigenetic Memory ◽  
Cellular Processes ◽  
Mechanics Model ◽  
Cell Phenotypes

Epigenetic histone modifications play an important role in the maintenance of different cell phenotypes. The exact molecular mechanism for inheritance of the modification patterns over cell generations remains elusive. We construct a Potts-type model based on experimentally observed nearest-neighbor enzyme lateral interactions and nucleosome covalent modification state biased enzyme recruitment. The model can lead to effective nonlocal interactions among nucleosomes suggested in previous theoretical studies, and epigenetic memory is robustly inheritable against stochastic cellular processes.

scholarly journals Deficits in lung alveolarization and function after systemic maternal inflammation and neonatal hyperoxia exposure

2010 ◽  
Vol 108 (5) ◽  
pp. 1347-1356 ◽  
Author(s):  
Markus Velten ◽  
Kathryn M. Heyob ◽  
Lynette K. Rogers ◽  
Stephen E. Welty
Keyword(s):  
Pulmonary Function ◽  
Interstitial Fibrosis ◽  
Pulmonary Function Tests ◽  
Combined Treatment ◽  
Lung Mechanics ◽  
Diffuse Fibrosis ◽  
Maternal Inflammation ◽  
Hyperoxia Exposure ◽  
And Function ◽  
Neonatal Hyperoxia

Systemic maternal inflammation contributes to preterm birth and is associated with development of bronchopulmonary dysplasia (BPD). Infants with BPD exhibit decreased alveolarization, diffuse interstitial fibrosis with thickened alveolar septa, and impaired pulmonary function. We tested the hypothesis that systemic prenatal LPS administration to pregnant mice followed by postnatal hyperoxia exposure is associated with prolonged alterations in pulmonary structure and function after return to room air (RA) that are more severe than hyperoxia exposure alone. Timed-pregnant C3H/HeN mice were dosed with LPS (80 μg/kg) or saline on gestation day 16. Newborn pups were exposed to RA or 85% O2 for 14 days and then to RA for an additional 14 days. Data were collected and analyzed on postnatal days 14 and 28. The combination of prenatal LPS and postnatal hyperoxia exposure generated a phenotype with more inflammation (measured as no. of macrophages per high-power field) than either insult alone at day 28. The combined exposures were associated with a diffuse fibrotic response [measured as hydroxyproline content (μg)] but did not induce a more severe developmental arrest than hyperoxia alone. Pulmonary function tests indicated that hyperoxia, independent of maternal exposure, induced compliance decreases on day 14 that did not persist after RA recovery. Either treatment alone or combined induced an increase in resistance on day 14, but the increase persisted on day 28 only in pups receiving the combined treatment. In conclusion, the combination of systemic maternal inflammation and neonatal hyperoxia induced a prolonged phenotype of arrested alveolarization, diffuse fibrosis, and impaired lung mechanics that mimics human BPD. This new model should be useful in designing studies of specific mechanisms and interventions that could ultimately be utilized to define therapies to prevent BPD in premature infants.

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