Ira M. Katz

Ira M. Katz

PhD

About

123
Publications
17,408
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
1,823
Citations
Citations since 2016
47 Research Items
771 Citations
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
Introduction
Ira M. Katz is a consultant in Biomedical Engineering and Mechanical Engineering primarily related to the development of medical gas therapies.
Additional affiliations
August 2001 - January 2006
Lafayette College
Position
  • Director of Mechanical Engineering Laboratories and Chemical Hygiene Coordinator

Publications

Publications (123)
Article
Full-text available
Background: The aim of this study was to observe dynamic pressure and flow measurements during the breathing cycle with different concentrations of xenon in patients without pulmonary disease to provide a better understanding of the mechanical-physiological effects of gas mixtures for anesthesia and other potential applications. Ventilation and res...
Article
Full-text available
High flow nasal cannula (HFNC) therapy has been previously shown to produce positive upper airway pressures in adult and child patients. This work aimed to evaluate and quantify the effects of HFNC flowrate and gas type on airway pressures measured in vitro in infant airway replicas. Ten realistic infant airway replicas, extending from nares to tra...
Article
Several studies based on in vivo or in vitro models have found promising results for the noble gas argon in neuroprotection against ischaemic pathologies. The development of argon as a medicinal product includes the requirement for toxicity testing through non-clinical studies. The long exposure period of animals (rats) during several days results...
Article
Full-text available
Using midbrain cultures, we previously demonstrated that the noble gas xenon is robustly protective for dopamine (DA) neurons exposed to l-trans-pyrrolidine-2,4-dicarboxylate (PDC), an inhibitor of glutamate uptake used to generate sustained, low-level excitotoxic insults. DA cell rescue was observed in conditions where the control atmosphere for c...
Article
Introduction: Medical air (MA) is widely used in hospitals, often manufactured onsite by compressing external ambient air and supplied through a local network piping system. Onsite production gives rise to a risk of impurities that are governed by the same pharmacopoeia purity standards applicable to commercially produced MA. The question to be add...
Article
Full-text available
Noble gases are chemically inert and it was therefore thought they would have little effect on biology. Paradoxically, it was found they do exhibit a wide range of biological effects, many of which are target-specific and potentially useful, and some of which have been demonstrated in vivo. The underlying mechanisms by which useful pharmacology, su...
Article
Full-text available
When administered in relatively high concentrations the mechanical properties of inhaled gas can become significantly different from air. This fact has implications in mechanical ventilation where adequate respiration and injury to the lungs or respiratory muscles can worsen morbidity and mortality. Here we use an engineering pressure loss model to...
Article
Full-text available
Background: Supplemental oxygen therapy is widely used in hospitals and in the home for chronic care. However, there are several fundamental problems with the application of this therapy such that patients are often exposed to arterial oxygen concentrations outside of the intended target range. This paper reports volume-averaged tracheal oxygen co...
Article
Background: High flow nasal cannula therapy is a form of respiratory support which delivers high flow rates of heated, humidified gas to the nares via specialized cannula. Two primary mechanisms of action attributed to the therapy are the provision of positive airway pressure as well as clearance of CO2-rich exhaled gas from the upper airways. Me...
Article
Full-text available
Argon exerts neuroprotection. Thus, it might improve patients’ neurological outcome after cerebral disorders or cardiopulmonary resuscitation. However, limited data are available concerning its effect on pulmonary vessel and airways. We used rat isolated perfused lungs (IPL) and precision-cut lung slices (PCLS) of rats and humans to assess this top...
Article
Background: Portable oxygen concentrators (POCs) deliver oxygen in intermittent pulses. The challenge of establishing equivalence between continuous flow oxygen and nominal pulse flow settings on different POCs is well known. In vitro bench measurements and in silico mathematical modeling were used to compare the performance of 4 POCs versus conti...
Article
Full-text available
Introduction Medical air (MA) is widely used in hospitals, often manufactured onsite by compressing external ambient air and supplied through a local network piping system. Onsite production gives rise to a risk of impurities that are governed by the same pharmacopoeia purity standards applicable to commercially produced MA. The question to be addr...
Article
The chemically inert noble gases display a surprisingly rich spectrum of useful biological properties. Relatively little is known about molecular mechanisms behind these effects. It is clearly not feasible to conduct large numbers of pharmacological experiments on noble gases to identify activity. Computational studies of binding of noble gases and...
Article
Full-text available
In asthma and COPD, some airways of the tracheo‐bronchial tree can be constricted, from moderate narrowing up to closure. Those pathological patterns of obstructions affect the lung ventilation distribution. While some imaging techniques enable visualization and quantification of constrictions in proximal generations, no non‐invasive technique exis...
Article
Full-text available
The upper airway (UA) in humans is commonly modeled as a Starling resistor. However, negative effort dependence (NED) observed in some patients with obstructive sleep apnea (OSA) contradicts predictions based on the Starling resistor model in which inspiratory flow is independent of inspiratory driving pressure when flow is limited. In a respirator...
Article
The 21st Congress for the International Society for Aerosols in Medicine included, for the first time, a session on Pulmonary Delivery of Therapeutic and Diagnostic Gases. The rationale for such a session within ISAM is that the pulmonary delivery of gaseous drugs in many cases targets the same therapeutic areas as aerosol drug delivery, and is in...
Article
Background: Primary benefits of high flow nasal cannula therapy include washout of carbon dioxide rich exhaled gas and increased airway pressures during tidal breathing. This work reports on the influence of high flow nasal cannula outlet area on upper airways gas clearance and tracheal pressures using measurements in five realistic adult nose-thr...
Article
Under normal conditions we continuously breathe 78% nitrogen (N2) such that the body tissues and fluids are saturated with dissolved N2. For normobaric medical gas administration at high concentrations, the N2 concentration must be less than that in the ambient atmosphere; therefore, nitrogen will begin to be released by the body tissues. There is...
Article
Full-text available
Background Portable oxygen concentrators (POCs) typically include pulse flow (PF) modes to conserve oxygen. The primary aims of this study were to develop a predictive in vitro model for inhaled oxygen delivery using a set of realistic airway replicas, and to compare PF for a commercial POC with steady flow (SF) from a compressed oxygen cylinder....
Article
Full-text available
Computational models of gas transport and aerosol deposition frequently utilize idealized models of bronchial tree structure, where airways are considered a network of bifurcating cylinders. However, changes in the shape of the lung during respiration affect the geometry of the airways, especially in disease conditions. In this study, the internal...
Data
Distensibility data distribution. This is a histogram of the distribution of the distensibility data of the right and left lung for the airways of generation 3 and 4. The best-fit normal density function is also shown as a red line. (TIF)
Data
Distensibility probability plot. The probability plot comparing the distensibility data to the normal distribution (reference line—-), created for the right and left lung generation 3 and 4 data. It can be observed that the fit of the data to the reference line deteriorates when distensibility values exceed one. (TIF)
Data
Normalized hydraulic diameter data. The hydraulic diameter data are normalized to the hydraulic diameter calculated for the trachea and are collected for the same airway tree bronchial regions as the ones considered by Choi et al. [38] (where available). The data are give as average values ± standard deviation values. (DOCX)
Data
Distensibility box and whisker plot. A box-plot of the distensibility for all the available airways of generations 3 and 4. Outliers are observed at above and under 1.5 Inter-Quartile range. (TIF)
Data
Data processing file. This is the excel file used to gather and statistically analyze the bronchial tree morphometric information that are investigated in this study. The file contains the average inner diameter, average lumen area, average inner perimeter, calculated hydraulic diameter and several definitions for airway distensibility. The data ar...
Article
In spite of numerous clinical studies, there is no consensus on the benefit Heliox mixtures can bring to asthmatic patients in terms of work of breathing and ventilation distribution. In this article we use a 3D finite element mathematical model of the lung to study the impact of asthma on effort and ventilation distribution along with the effect o...
Article
Full-text available
Argon (Ar) is a noble gas with known organoprotective effects in rodents and in vitro models. In a previous study we failed to find a postconditioning effect of Ar during ex vivo lung perfusion (EVLP) on warm-ischemic injury in a porcine model. In this study, we further investigated a prolonged exposure to Ar to decrease cold ischemia-reperfusion i...
Article
In this article we develop a lung-ventilation model. The parenchyma is described as an elastic homogenized media. It is irrigated by a space-filling dyadic resistive pipe network, which represents the tracheo-bronchial tree. In this model the tree and the parenchyma are strongly coupled. The tree induces an extra viscous term in the system constitu...
Article
Full-text available
In this paper in vivo measurements and the results of an in silico analysis of the effects of fluid property variation on dynamic ventilation parameters during xenon anesthesia are presented. The in vivo measurements of dynamic ventilatory parameters were taken prior to surgery during the wash-in phase of xenon anesthesia. The in silico model is ba...
Article
Full-text available
Roughton and Forster (RF) proposed to split the lung diffusing capacity into two contributions describing first, diffusion to red blood cells (RBC), and second, capture by diffusion from the RBC surface and reaction with haemoglobin. Solving the diffusion-reaction equations for simplified capillary-RBC structures, we investigate the RF interpretati...
Article
Full-text available
A quantitative description of the morphology of lung structure is essential prior to any form of predictive modeling of ventilation or aerosol deposition implemented within the lung. The human lung is a very complex organ, with airway structures that span two orders of magnitude and having a multitude of interfaces between air, tissue and blood. As...
Data
Model Morphology Data.zip. A set of two files per subject containing the morphology and connectivity information of the airway tree (both “real” and “model” data). The _morphology.txt file includes the total lung volume of the subject lung in cm3 and the %volume per lobe. It also includes the following fields in each row (one row per airway): (i) V...
Article
In this paper we address a fundamental question regarding computational fluid dynamics (CFD) modeling within lung airways: does the inhaled volume during imaging have a significant effect on CFD computations of aerosol deposition? High resolution computed tomography (HRCT) images taken at mean lung volume (MLV) and at total lung capacity (TLC) obta...
Article
Full-text available
Oxygen treatment based on intermittent-flow devices with pulse delivery modes available from portable oxygen concentrators (POCs) depends on the characteristics of the delivered pulse such as volume, pulse width (the time of the pulse to be delivered), and pulse delay (the time for the pulse to be initiated from the start of inhalation) as well as...
Article
Full-text available
Background Inhaled nitric oxide (NO) is a selective pulmonary vasodilator used primarily in the critical care setting for patients concurrently supported by invasive or noninvasive positive pressure ventilation. NO delivery devices interface with ventilator breathing circuits to inject NO in proportion with the flow of air/oxygen through the circui...
Article
Full-text available
New gas therapies using inert gases such as xenon and argon are being studied, which require in vitro and in vivo preclinical experiments. Examples of the kinetics of gas transport during such experiments are analyzed in this paper. Using analytical and numerical models, we analyze an in vitro experiment for gas transport to a 96 cell well plate an...
Article
The noble gases represent an intriguing scientific paradox. They are extremely inert chemically but display a remarkable spectrum of clinically useful biological properties. Despite a relative paucity of knowledge of their mechanisms of action, some of the noble gases have been used successfully in the clinic. Studies with xenon have suggested that...
Article
Development of a new drug for the treatment of lung disease is a complex and time consuming process involving numerous disciplines of basic and applied sciences. During the 2015 Congress of the International Society for Aerosols in Medicine, a group of experts including aerosol scientists, physiologists, modelers, imagers, and clinicians participat...
Article
Background: Theoretical models suggest that He-O2 as carrier gas may lead to more homogeneous ventilation and aerosol deposition than air. However, these effects have not been clinically consistent and it is unclear why subjects may or may not respond to the therapy. Here we present 3D-imaging data of aerosol deposition and ventilation distributio...
Article
Full-text available
New gas therapies using inert gases such as xenon and argon are being studied, which would require chronically administered repeating doses. The pharmacokinetics of this type of administration has not been addressed in the literature. A physiologically based pharmacokinetics (PBPK) model for humans, pigs, mice, and rats has been developed to invest...
Article
Background Evidence supports the use of ex vivo lung perfusion (EVLP) as a platform for active reconditioning before transplantation to increase the potential donor pool and to reduce the incidence of primary graft dysfunction. A promising reconditioning strategy is the administration of inhaled noble gases based on their organoprotective effects....
Article
Full-text available
Background Helium/oxygen therapies have been studied as a means to reduce the symptoms of obstructive lung diseases with inconclusive results in clinical trials. To better understand this variability in results, an exploratory physiological study was performed comparing the effects of helium/oxygen mixture (78%/22%) to that of medical air. Methods...
Article
Full-text available
Computational 3D models of the human lung are routinely being used to study lung physiology and estimate aerosol deposition and gas distribution mechanics in the human airway tree. In this study, two separate models were used to fully describe the human respiratory system. The first describes the bronchial and bronchiolar part of the respiratory sy...
Article
Full-text available
A previous PET-CT imaging study of 14 bronchoconstricted asthmatic subjects showed that peripheral aerosol deposition was highly variable among subjects and lobes. The aim of this work was to identify and quantify factors responsible for this variability. A theoretical framework was formulated to integrate four factors affecting aerosol deposition:...
Article
Full-text available
Computer modeling is used to predict inhaled aerosol deposition in the lung based on definition of the aerosol characteristics and the breathing pattern and airway anatomy of the subject. Validation of the models is limited by the lack of detailed experimental data. Three-dimensional imaging provides an opportunity to address this unmet need. Radio...
Article
Full-text available
Computational Fluid Dynamics simulations of inspiratory airflow in asymmetric bifurcations have been performed in order to determine the influence of the asymmetry and Reynolds number on pressure losses over a physiologically relevant range for pulmonary airways; thus the results of this work can contribute to the understanding of respiratory venti...
Article
Full-text available
Oxygen capture in the lung results from the intimate dynamic interaction between the space- and time-dependent oxygen partial pressure that results from convection-diffusion and oxygen extraction from the alveolar gas and the space and time dependence of oxygen trapping by the red blood cells flowing in the capillaries. The complexity of the proble...
Article
Despite very low Reynolds numbers in the bronchial ducts, acinar flow associated with wall motion can exhibit irreversibility and chaoticity, two efficient features of convective mixing contributing to alveolar dispersion. This article describes a new computational fluid dynamics (CFD) approach in which an Eulerian continuous scalar field transport...