Respiratory System Dynamical Mechanical Properties: Modeling in Time and Frequency Domain

Abstract Background. This study was conceived to provide systematic data about lung mechanics during early phases of CoVID-19 pneumonia, as long as to explore its variations during prone positioning. Methods. We enrolled four patients hospitalized in the Intensive Care Unit of “M. Bufalini” hospital, Cesena (Italy); after the positioning of an esophageal balloon, we measured mechanical power, respiratory system and transpulmonary parameters and arterial blood gases every 6 hours, just before decubitus change and 1 hour after prono-supination. Results. Both respiratory system and transpulmonary compliance and driving pressure confirmed the pseudo-normal respiratory mechanics of early CoVID-19 pneumonia (respectively, CRS 40.8 ml/cmH2O and DPRS 9.7 cmH2O; CL 53.1 ml/cmH2O and DPL 7.9 cmH2O). Interestingly, prone positioning involved a worsening in respiratory mechanical properties (CRS,SUP 56.3 ml/cmH2O and CRS,PR 41.5 ml/cmH2O – P 0.37; CL,SUP 80.8 ml/cmH2O and CL,PR 53.2 ml/cmH2O – P 0.23). Conclusions. Despite the severe ARDS pattern, respiratory system and lung mechanical properties during CoVID-19 pneumonia are pseudo-normal and tend to worsen during pronation. Trial registration. Restrospectively registered.

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Effects of Combined Exercise Training in Respiratory System Mechanical Properties and Inflammation in Rats with Hepatopulmonary Syndrome

10.1164/ajrccm-conference.2019.199.1_meetingabstracts.a2067 ◽

2019 ◽

Author(s):

E. Nascimento ◽

W. Nunes ◽

S. Costa-Silva ◽

M. Roza ◽

O. Nobrega ◽

...

Keyword(s):

Mechanical Properties ◽

Exercise Training ◽

Respiratory System ◽

Hepatopulmonary Syndrome ◽

Combined Exercise ◽

Combined Exercise Training

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Ontogeny of respiratory control and pulmonary mechanics in newborn rabbits

Journal of Applied Physiology ◽

10.1152/jappl.1985.59.5.1477 ◽

1985 ◽

Vol 59 (5) ◽

pp. 1477-1486 ◽

Cited By ~ 4

Author(s):

M. M. Grunstein ◽

D. T. Tanaka

Keyword(s):

Mechanical Properties ◽

Tidal Volume ◽

Respiratory System ◽

Minute Ventilation ◽

Work Of Breathing ◽

Relative Volume ◽

Respiratory Pattern ◽

Pulmonary Mechanics ◽

Volume Loss ◽

Age Related

Maturation of the respiratory pattern and the active and passive mechanical properties of the respiratory system were assessed in 19 tracheotomized rabbits (postnatal age range: 1–26 days) placed in a body plethysmograph. With maturation both minute ventilation and tidal volume significantly increased, whereas respiratory frequency decreased. When normalized for body weight (kg) both the passive (Rrs X kg) and active (R'rs X kg) resistances of the respiratory system significantly increased with age, whereas the corresponding passive (Crs X kg-1) and active (C'rs X kg-1) compliances significantly decreased. At any given age R'rs X kg only slightly exceeded Rrs X kg, whereas C'rs X kg-1 was significantly lower than Crs X kg-1. Moreover, the maturational increases in Rrs X kg and R'rs X kg exceeded the corresponding decreases in Crs X kg-1 and C'rs X kg-1, resulting in significant age-related increases in both the passive (tau rs) and active (tau'rs) time constants of the respiratory system. Due to the age-related increases in tau'rs, producing a delayed volume response to any given inspiratory driving pressure, the relative volume loss obtained at any time during inspiration was greater in the maturing rabbit. On the other hand, because of concomitant compensatory changes in respiratory pattern, evidenced by increases in inspiratory duration with age, the end-inspiratory tidal volume loss in the maturing animal was maintained generally less than 10% at all postnatal ages. Thus maturational changes in respiratory pattern appear coupled to changes in the active mechanical properties of the respiratory system. The latter coupling serves to optimize the transduction of inspiratory pressure into volume change in a manner consistent with establishing the minimum inspiratory work of breathing during postnatal development.

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IODINE DOPING OF PREVULCANIZED NATURAL RUBBER LATEX AND ITS EFFECT ON DYNAMICAL MECHANICAL PROPERTIES

Rubber Chemistry and Technology ◽

10.5254/1.3592289 ◽

2011 ◽

Vol 84 (4) ◽

pp. 474-481

Author(s):

P. Predeep ◽

S. Najidha

Keyword(s):

Mechanical Properties ◽

Natural Rubber ◽

Natural Rubber Latex ◽

Iodine Concentration ◽

Potential Candidate ◽

Iodine Doping ◽

Rubber Latex ◽

Energy Storage Devices ◽

Electrically Conducting ◽

Dynamical Mechanical Properties

Abstract Conducting polymers are finding new application areas in energy storage devices, optoelectronics, actuators etc. Iodine doped semiconducting prevulcanized natural rubber latex (RVNRL) is a potential candidate for many such applications. We had already demonstrated for the first time that pre-vulcanized NR latex can be doped by iodine to become electrically conducting and doping process is not affecting the flexibility or processability of the films. Synthesis and characterization of intrinsically electric conducting preculcanized natural rubber latex are briefly discussed. Further, dynamical mechanical properties of these doped RVNRL are reported. The glass transition (Tg) temperature of the chemically doped polyisoprene material was found to be shifted to higher temperature region with the iodine concentration. However, the mechanical properties are found to decrease at higher concentration of the dopant after showing an increasing trend as in the case of Tg at lower doping levels. An effort has also been made to explain this visibly contradictory behavior.

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