Positive end-expiratory pressure and surfactant administration mode influence function in ex-vivo premature sheep lungs.

AIM: Respiratory distress syndrome often necessitates endotracheal surfactant administration in extremely preterm infants. Our study aimed to explore a multi-modal simulation tool for investigating treatment strategies in ex vivo sheep lungs during spontaneous breathing. METHODS: An electromechanical lung simulator (xPULM) mimicking spontaneous breathing was coupled with a non-aerated premature sheep lung, replicating a premature respiratory system. Changes in tidal volume for different positive end-expiratory pressure (PEEP) levels prior to and after either bolus or nebulised surfactant administration were compared. RESULTS: In two preterm sheep lungs, we observed a progressive decline in tidal volume with increasing PEEP levels prior to surfactant delivery from 0.30 ± 0.01 mL at zero PEEP to 0.04 ± 0.01 mL at 15 cmH2O PEEP. Our measurements showed that both bolus (p < 0.05) and nebulised (p < 0.05) surfactant administration resulted in a significant increase in tidal volume, with no significant difference (p = 0.71) between the two methods. CONCLUSION: The experimental setup demonstrated the feasibility of xPULM for investigating the effectiveness of different PEEP levels and modes of surfactant administration with respect to tidal volume in premature sheep lungs. The lack of adequate lung water resorption in our model warrants further investigations.

Experimental Evaluation of Dry Powder Inhalers during Inhalation and Exhalation Using a Model of the Human Respiratory System (xPULM™).

Dry powder inhalers are used by a large number of patients worldwide to treat respiratory diseases. The objective of this work is to experimentally investigate changes in aerosol particle diameter and particle number concentration of pharmaceutical aerosols generated by four dry powder inhalers under realistic inhalation and exhalation conditions. To simulate patients undergoing inhalation therapy, the active respiratory system model (xPULM™) was used. A mechanical upper airway model was developed, manufactured, and introduced as a part of the xPULM™ to represent the human upper respiratory tract with high fidelity. Integration of optical aerosol spectrometry technique into the setup allowed for evaluation of pharmaceutical aerosols. The results show that there is a significant difference (p < 0.05) in mean particle diameter between inhaled and exhaled particles with the majority of the particles depositing in the lung, while particles with the size of (>0.5 µm) are least influenced by deposition mechanisms. The fraction of exhaled particles ranges from 2.13% (HandiHaler®) over 2.94% (BreezHaler®), and 6.22% (Turbohaler®) to 10.24% (Ellipta®). These values are comparable to previously published studies. Furthermore, the mechanical upper airway model increases the resistance of the overall system and acts as a filter for larger particles (>3 µm). In conclusion, the xPULM™ active respiratory system model is a viable option for studying interactions of pharmaceutical aerosols and the respiratory tract regarding applicable deposition mechanisms. The model strives to support the reduction of animal experimentation in aerosol research and provides an alternative to experiments with human subjects.

Changes of particle deposition caused by different breathing patterns during active lung simulation.

Aerosols are an integral part of everyday life and as such are inhaled under various conditions and circumstances. These may vary based on the health and activity status of an individual. The aim of this work is to analyse the particle deposition mechanisms during the simulation of three different breathing patterns using an aerosol representing the PM1 fraction of fine particles. The active electro-mechanical lung simulator xPULM is utilized as a driving force and is combined with a non-invasive direct reading optical aerosol measurement system. Results show differences between the number of deposited particles for the three breathing patterns and for the three typical size ranges of airborne particles. Overall, the presented approach demonstrates the possibility of determining the changes of aerosol uptake based on different breathing patterns using the electro-mechanical lung simulator and laboratory produced aerosols. Further measurement cycles must be performed in order to validate the found interactions and to characterize the major influencing parameters.

Electro-mechanical Lung Simulator Using Polymer and Organic Human Lung Equivalents for Realistic Breathing Simulation.

Simulation models in respiratory research are increasingly used for medical product development and testing, especially because in-vivo models are coupled with a high degree of complexity and ethical concerns. This work introduces a respiratory simulation system, which is bridging the gap between the complex, real anatomical environment and the safe, cost-effective simulation methods. The presented electro-mechanical lung simulator, xPULM, combines in-silico, ex-vivo and mechanical respiratory approaches by realistically replicating an actively breathing human lung. The reproducibility of sinusoidal breathing simulations with xPULM was verified for selected breathing frequencies (10-18 bpm) and tidal volumes (400-600 ml) physiologically occurring during human breathing at rest. Human lung anatomy was modelled using latex bags and primed porcine lungs. High reproducibility of flow and pressure characteristics was shown by evaluating breathing cycles (nTotal = 3273) with highest standard deviation |3σ| for both, simplified lung equivalents ([Formula: see text] = 23.98 ± 1.04 l/min, µP = -0.78 ± 0.63 hPa) and primed porcine lungs ([Formula: see text] = 18.87 ± 2.49 l/min, µP = -21.13 ± 1.47 hPa). The adaptability of the breathing simulation parameters, coupled with the use of porcine lungs salvaged from a slaughterhouse process, represents an advancement towards anatomically and physiologically realistic modelling of human respiration.

Development of a Multidisciplinary and Telemedicine Focused System Database.

BACKGROUND: Tele-rehabilitation at home is one of the promising approaches in increasing rehabilitative success and simultaneously decreasing the financial burden on the healthcare system. OBJECTIVES: Novel and mostly mobile devices are already in use, but shall be used in the future to a higher extent for allowing at home rehabilitation processes at a high quality level. The combination of exercises, assessments and available equipment is the basic objective of the presented database. METHODS: The database has been structured in order to allow easy-to-use and fast access for the three main user groups. Therapists - looking for exercise and equipment combinations - patients - rechecking their tasks for home exercises - and manufacturers - entering their equipment for specific use cases. RESULTS: The database has been evaluated by a proof of concept study and shows a high degree of applicability for the field of rehabilitative medicine. Currently it contains 110 exercises/assessments and 111 equipment/systems. CONCLUSION: Foundations of presented database are already established in the rehabilitative field of application, but can and will be enhanced in its functionality to be usable for a higher variety of medical fields and specifications.