Automatic air volume control system for ventilation of two patients using a single ventilator: a large animal model study.

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.

Independent Lung Ventilation-Experimental Studies on a 3D Printed Respiratory Tract Model.

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.

Effect of electrospinning process variables on the size of polymer fibers and bead-on-string structures established with a 23 factorial design.

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.

Predicted Deposition of E-Cigarette Aerosol in the Human Lungs.

BACKGROUND: Health effects of inhaling aerosol produced by electronic cigarettes (ECs) are still uncertain. This work analyzes ECs as specific inhalation devices, which can be characterized by aerodynamic resistance, size distribution of released droplets, and predicted regional and total lung deposition as a function of inhalation maneuver. METHODS: The internal resistance of two types of EC and a conventional cigarette was evaluated by measuring ΔP-Q curves. Particle size distribution in EC-emitted mist was determined by laser diffraction. The measured data were used to calculate lung deposition based on two approaches: multipath particle dosimetry model (MPPD) and Finlay-Martin correlations. Computations were done for the set of ventilation parameters of an EC user, and also for a by-stander. RESULTS: Tested ECs had higher aerodynamic resistance (1.6-1.9 mbar(0.5) min/L) than tobacco cigarette (0.56 mbar(0.5) min/L), and these values are much above the high-resistant DPIs. The average mass median diameter of droplets emitted from ECs was 410 nm, with the average GSD = 1.6. Predicted total lung deposition of the mainstream aerosol was 15%-45% depending on the breathing scheme. An expected increase of particle size in the exhaled aerosol led to predictions of 15%-30% deposition efficiency during passive vaping. CONCLUSIONS: 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.

The oxidation status of ALDH3A1 in human saliva and its correlation with antioxidant capacity measured by ORAC method.

Oxidation status of the salivary aldehyde dehydrogenase (ALDH) was measured in healthy human population using two-assay fluorimetric method and compared with antioxidant capacity (ORAC) in non-smoking and heavy smokers group. Influence of high or low antioxidant diet was also examined. Except for the group of smokers, the salivary ALDH oxidation degree in human saliva was not correlated with antioxidant capacity. Simultaneously direct administration of the antioxidant-containing drug, Fluimucil, resulted in short-term, but statistically significant increase of the reduced (active) form of the enzyme, presumably due to a radical-scavenging activity of the drug.

[Pain, analgesia, and sex]. / Ból, analgezja, plec.

There is a large volume of data regarding sex differences in pain sensitivity and analgesia in both animals and in humans. It is difficult to analyze all the complex observations and find new aims for future studies. The main aspects of sex differences in sensitivity to and analgesia of experimental and clinical pain are described in this paper. The most important parameters which influence sex differences in pain perception are also presented.

Sex dependent antinociceptive activity and blood pressure changes in SHR, WKY and WAG rat strains after diclofenac treatment.

Antinociceptive action of diclofenac (non-opioid analgesic) was investigated in male and female normotensive (WKY) and genetically established hypertensive (SHR) and normotensive WAG. The drug was administered subcutaneously in doses of 10 mg/kg body weight and per os 20 mg/kg and 40 mg/kg. Statistically significant differences in pain threshold were reported between male and female rats of investigated strains. Phase of sex cycle in female rats was determined along with the pain threshold level. Arterial hypertension control in WAG and SHR female rats performed in parallel showed considerable changes in blood pressure after diclofenac administration in the estrus phase. There were several correlated effects in blood pressure and pain threshold after drugs administration. The results obtained may explain the non-uniformity in antinociceptive action of analgesics in both sexes during long-term therapy in different strains.

[A relationship between autonomy and mental disorders]. / Zwiazki miedzy autonomia a zaburzeniami psychicznymi.

The aim of this article is to present three new cognitive approaches to autonomy and it's importance for pathology. According to Ryan and Deci's self-determination theory autonomy is manifested through intrinsically motivated behaviour. As the individual develops it's autonomous activity is expanded gradually by the integration of regulatory processes. Being autonomous, one can modulate and manage one's emotions and impulses, is aware of emotional states and hence is capable of behaving adequately. Pathology develops when the problems with the integration of external regulatory processes occur. According to Toru Sato, there are two parts of the self--autonomy and relatedness. The first one focuses on control over one's environment and one's bodily functioning. For the other one "being associated" with one or more persons is a goal in itself. For correct functioning the person's autonomy and relatedness needs should be satisfied. Both self-systems are involved in the process, which should result in their integration. Sato claims that too much stress put on one of the systems weakens the other one. The person satisfies only one need and it is crucial for it's mental condition. Pathological mechanisms are culturally conditioned. Beck describes two personality dimensions--autonomy and sociotropy. Autonomy refers to the personal interest in independence, individuality and attaining personal goals. The autonomous individual takes it's sense of well-being from personal achievements and control over her/his own activity and environment. The author claims that both highly autonomous and highly sociotropic individuals are vulnerable to depression.