ECs are characterized by high inhalatory resistance, so they require stronger physical effort to transfer cloud of droplets to the lungs, as compared, for example, to DPIs. A significant amount of aerosol is then exhaled, forming an unintentional source of particles to which by-standers are exposed. From this perspective, ECs are not optimal personal aerosol delivery devices.

This work examines the effect of selected process parameters on the diameter of uniform and heterogeneous fibers (with and without bead-on-string structures) and the size of beads obtained during the electrospinning process. A 23 factorial design was performed to determine the influence of the following factors: electrical voltage, flow rate and dynamic viscosity of the poly(vinylpyrrolidone) ethanolic solution. Factorial design enables the analysis of the mathematical relationship between the chosen factors and the response with a minimum number of experiments. The factor having the most significant impact on the size of beaded fibers and beads was the solution viscosity, while the voltage had the greatest influence on the bead-free fiber diameter. The interactions between the studied factors were also analyzed. It was found that the presented method can be used for the design of an optimal and cost-effective electrospinning process, allowing the desired product to be obtained with expected features.

Understanding the influence of process conditions on the properties of pharmaceutical products is critical to their optimal and cost-effective design and manufacture. The aim of this study was to investigate the effect of changing processing variables on the physical properties of spray-dried mannitol and co-spray-dried mannitol/disodium cromoglycate (DSCG) formulations intended for therapeutic inhalation. A 2 4 full factorial design was performed to assess the consequences of altering the following spray-drying parameters: feed flow rate, nozzle gas flow rate, drying gas inlet temperature, and aspirator capacity (drying gas flow rate). Aqueous solutions of mannitol and mannitol/DSCG were spray-dried using a laboratory-scale spray dryer, and the products were characterized in terms of particle size distribution, powder yield, and particle morphology. These physical properties were found to be affected mainly by two processing variables: nozzle gas flow rate and drying gas inlet temperature. In addition, optimal conditions for the production of inhalable mannitol powders were obtained, generating a yield of 90% by weight of round and smooth particles with a volume median diameter of 4.28 μm. Mannitol/DSCG formulations co-spray-dried in the same conditions had similar characteristics. The results of this study can be applied to controlled formulation of various spray-dried powders for inhalation.

No abstract

Independent lung ventilation (ILV) is a life-saving procedure in unilateral pulmonary pathologies. ILV is underused in clinical practice, mostly due to the technically demanding placement of a double lumen endotracheal tube (ETT). Moreover, the determination of ventilation parameters for each lung in vivo is limited. In recent years, the development of 3D printing techniques enabled the production of highly accurate physical models of anatomical structures used for in vitro research, considering the high risk of in vivo studies. The purpose of this study was to assess the influence of double-lumen ETT on the gas transport and mixing in the anatomically accurate 3D-printed model of the bronchial tree, with lung lobes of different compliances, using various ventilation modes. The bronchial tree was obtained from Respiratory Drug Delivery (RDD Online, Richmond, VA, USA), processed and printed by a dual extruder FFF 3D printer. The test system was also composed of left side double-lumen endotracheal tube, Siemens Test Lung 190 and anesthetic breathing bag (as lobes). Pressure and flow measurements were taken at the outlets of the secondary bronchus. The measured resistance increased six times in the presence of double-lumen ETT. Differences between the flow distribution to the less and more compliant lobe were more significant for the airways with double-lumen ETT. The ability to predict the actual flow distribution in model airways is necessary to conduct effective ILV in clinical conditions.

No abstract

The COVID-19 pandemic outbreak led to a global ventilator shortage. Hence, various strategies for using a single ventilator to support multiple patients have been considered. A device called Ventil previously validated for independent lung ventilation was used in this study to evaluate its usability for shared ventilation. We performed experiments with a total number of 16 animals. Eight pairs of pigs were ventilated by a ventilator or anesthetic machine and by Ventil for up to 27 h. In one experiment, 200 ml of saline was introduced to one subject’s lungs to reduce their compliance. The experiments were analyzed in terms of arterial blood gases and respiratory parameters. In addition to the animal study, we performed a series of laboratory experiments with artificial lungs (ALs). The resistance and compliance of one AL (affected) were altered, while the tidal volume (TV) and peak pressure (Ppeak) in the second (unaffected) AL were analyzed. In addition, to assess the risk of transmission of pathogens between AL respiratory tracts, laboratory tests were performed using phantoms of virus particles. The physiological level of analyzed parameters in ventilated animals was maintained, except for CO2 tension, for which a permissive hypercapnia was indicated. Experiments did not lead to injuries in the animal’s lungs except for one subject, as indicated by CT scan analysis. In laboratory experiments, changes in TV and Ppeak in the unaffected AL were less than 11%, except for 2 cases where the TV change was 20%. No cross-contamination was found in simulations of pathogen transmission. We conclude that ventilation using Ventil can be considered safe in patients undergoing deep sedation without spontaneous breathing efforts.

The COVID-19 pandemic outbreak led to a global ventilator shortage. Hence, different strategies to use a single ventilator to support multiple patients are considered. A mechatronic system Ventil divides and automatically controls gas volume pumped through two channels and was successfully validated in independent lung ventilation. We used Ventil in a series of experiments on a large animal model to verify its usability for ventilation in two patients using a single ventilator. The results of investigations on 12 pigs showed that the physiological level of respiratory parameters was maintained for 24 hours. Application of Ventil did not lead to injuries in the lungs, as indicated by CT scan analysis. We conclude that ventilation using Ventil can be considered safe in patients subjected to deep sedation without spontaneous breathing efforts.