Aerosolized drug delivery to the human lungs for asthma treatment has long been studied and yet the relationship between the delivery efficacy and the inter-subject variability due to gender, age, and disease severity remains unclear. A recent imaging-based cluster analysis on a population of asthmatic patients identifies four clusters with distinct structural and functional characteristics. The use of cluster membership to explore inter-subject variability by investigating numerically the air flow and particle transport in representative subjects of the asthmatic clusters on inhalation drug delivery in asthma sub-populations is proposed. Large-eddy simulations using computed tomography (CT)-based airway models were performed with a slow and deep breathing profile corresponding to application of a metered dose inhaler. Physiologically consistent subject specific boundary conditions in peripheral airways were produced using an image registration technique and a resistance network compliance model. Particle simulations and final deposition statistics were calculated for particle sizes ranging from 1–8 μm. The results suggested an emphasis on the importance of airway constriction for regional particle deposition and prominent effects of local features in lobar, segmental, and sub-segmental airways on overall deposition patterns. Asthmatic clusters characterized by airway constriction had an increase in deposition efficiency in lobar, segmental, and sub-segmental airways. Local constrictions produced jet flows that impinged on distal bifurcations and resulted in large inertial depositions. Decreased right main bronchus (RMB) branching angle decreased the fraction of particles ventilated to the right upper lobe (RUL). Cluster-based computational fluid dynamics results demonstrate particle deposition characteristics associated with imaging based variables that could be useful for future drug delivery improvements. One method for circumventing low deposition in small airways due to constriction in tracheobronchial airways is through hygroscopic growth of aerosols for inhalation. Hygroscopic materials have an affinity for water and can enlarge in size significantly as they traverse through respiratory tract. Hygroscopic growth has shown promise as a viable drug delivery method for decreasing deposition in the upper tracheobronchial region and increasing drug penetration and retention in small airways. Current models for hygroscopic growth models show promise in predicting steady state final diameter aerosol droplet sizes, but much uncertainty in predicting transient effects exists. This paper discusses in detail one such growth model and modifies it to include realistic spatial temperature and humidity variations associated with the lung. The growth model is simplified through grouping of terms and is then solved using MATLAB ODE 45 solver. The model is compared to experimentally acquired in vitro data for validation. The results do not show good agreement with the model, and suggests that additional factors exist that inhibit aerosol droplet growth from commencing immediately upon entering the respiratory tract like is assumed true in literature. This paper briefly hypothesizes for reasons for model and data disagreement and limitations of current growth models.

No description available.

L’intervention de Fontan est une chirurgie palliative pour les cardiopathies congénitales univentriculaire. A long terme, la défaillance cardiaque, l’hypertension artérielle pulmonaire(HTAP) et l’entéropathie exsudative peuvent mener à l’échec tardif du Fontan.Une mise au point clinique a été realisée en se focalisant secondairement sur les patients adultes.L’intérêt de la cavo bipulmonaire (CBP), étape intermédiaire au Fontan, dans certains cas de retours veineux pulmonaires anormaux totaux a été décrite. Afin d’affiner de futures études cliniques, nous avons discuté de l’intérêt du Brain NatriureticPeptide en post opératoire de Fontan. Nous avons démontré la fiabilité d’une nouvelle technologiede l’oxyme´trie de pouls chez des enfants cyanosés et la non fiabilité d’un nouveau dispositifd’impédancemétrie pour le monitorage non invasif du de´bit cardiaque en comparaison avecun cathéter artériel pulmonaire.Un modèle animal viable et chronique de la CBP a été développé. Il a montré que le flux pulsatileantérograde empêche la formation de fistules artério-veineuses pulmonaires (FAVP), améliorel’hématose et atténue le développement de l’HTAP soutenant cliniquement le maintien de ce fluxlors de la création d’une CBP. Par ailleurs, la perte de pulsatilité, en diminuant le contrainte de cisaillement, entraîne unediminution de l’eNOS synthase et une réponse altérée vaso-relaxante dépendante de l'endothélium artérielle pulmonaire. La micropulsatilité limite ces effets délétères. Ces résultats impliquent desthérapies potentielles contre l’HTAP du Fontan, en maintenant un débit pulmonaire accessoire et la modulation pharmaceutique vaso-relaxante non endothélium-dépendante / The Fontan surgery is a palliative surgery for univentricular congenital heart disease. On the longterm, heart failure, pulmonary arterial hypertension (PAH) and exudative enteropathy may lead tothe Fontan failure.A clinical adjustment has been realized by focusing secondarily on adult patients. The advantage, insome cases of total anomalous pulmonary venous return, of the bidirectional cavopulmonary (BCP),which is an intermediate stage of Fontan, has been described.In order to prepare future clinical studies, we have discussed about Brain Natriuretic Peptide inpostoperative Fontan surgery. We have demonstrated the reliability of a new technology of pulseoxymetry in cyanotic children and the unreliability of a new device of impedance for non-invasivemonitoring of cardiac outpout in comparison with pulmonary arterial catheter.A viable chronic animal model of bidirectional cavo-pulmonary (BCP) has been developed. Itshowed that the antegrade pulsatile flow prevents the formation of pulmonary arteriovenous fistulas(PAVMs) ,improves hematosis and attenuates the development of PAH clinically supporting themaintenance of this flow when creating a BCP.Moreover, the loss of pulsatility while reducing the shear stress causes a decrease in e-NOSsynthase and a dependent vaso-relaxing altered response of the pulmonary arterial endothelium. Themicropulsatility limits these deleterious effects. These results imply potential therapies against thePAH of Fontan surgery, maintaining an accessory pulmonary blood flow and the pharmaceuticalvaso-relaxing non-endothelium dependent modulation.