SEMINAR: Variability in respiration: possible origins, impact on cells and clinical implications
|Variability in respiration: possible origins, impact on cells and clinical implications : School of Anatomy, Physiology & Human Biology Seminar Series
The Seminar: All respiratory variables including tidal volume and respiratory rate display significant cycle by cycle variabilities. The purpose of this talk is to 1) show how observed variabilities can provide useful clinical information; 2) explore the origins of respiratory variability; 3) demonstrate the cellular consequences of variability in stretch; and 4) review possibilities of implementing variabilities in life-support systems.
Analysis of variability in respiratory physiology has been shown to contain clinical information and can be used to diagnose diseases or predict exacerbation risk. For example, peak expiratory flows and respiratory resistance have been found to exhibit long-range correlations in asthmatic subjects. We introduced clinically useful risk measures such as the conditional probability that given the peak flow or resistance today, what is the probability that an exacerbation occurs within a given time period.
Virtually no study has examined the origin of variabilities. The respiratory rhythm generator is a neural network that generates rhythmic breathing. Computational models of the neural oscillator produce periodic rhythm without variability. However, introducing external noise in the tonic inputs to the neural network coupled with the passive mechanical properties of the respiratory system reproduces the characteristics of the observed variabilities related to spontaneous breathing suggesting that variability is fundamentally linked to the brain respiratory oscillator.
A consequence of variability in tidal breathing is that all adherent cells in the respiratory system are exposed to variable tidal stretch patterns. Our experimental data indicate that variability in stretch applied to cells significantly alters and often enhances essential cell functions such as cytoskeletal organization, surfactant secretion or mitochondrial ATP generation. Thus, variability at the level of the cell is essential for normal cell function that must have adapted to the presence of variabilities over hundreds of millions of years of evolution.
As a practical application, introducing variability in artificial life-support systems such as mechanical ventilators should improve the healing of the injured lung. We provide evidence that introducing variability in tidal volume during mechanical ventilation improves lung function such as compliance and gas exchange as well as reduces cellular inflammation and ameliorates surfactant secretion. Thus, variability in mechanical ventilation could reduce the time on the ventilator and mortality for patients with acute lung injury.
The Speaker: Prof. Béla Suki was born in Hungary and graduated as a physicist from the József Attila University in Szeged, Hungary. He received his PhD in biomechanics from the same university in 1987. His thesis advisor was Dr. Zoltán Hantos. As a post-doctoral fellow, Dr. Suki spent a year working with Dr. René Peslin at INSERM in Nancy, France in 1988 and then a year working with Dr. Jason Bates in the Meakins-Christie Laboratories in 1990. In 1991, he joined the Department of Biomedical Engineering at Boston University as a research associate where he became assistant professor and then full professor in 2007. In the same year, he became a Fellow of the American Institute for Medical and Biological Engineering as well as Elected Biomedical Engineering Professor of the Year at Boston University. In 2009, he received a presidential award from the National Institutes of Health. He has organized and chaired many sessions and tracks at various international meetings and given over 110 invited talks at meetings, universities and hospitals. He has 2 patents and published 8 book chapters and 185 peer reviewed articles some of which appeared in top journals such as Nature, Lancet, PNAS and Phys Rev Lett. His current research includes variability in mechanical ventilation applied to infants, the interaction of enzymes and mechanical forces, the progressive nature of pulmonary emphysema, the role of variability in biology and modeling complex phenomena in physiology and biology.
Professor Bela Suki, Biomedical Engineering, Boston University, USA
Room 1.81, Anatomy, Physiology & Human Biology buiding north
: 6488 3313
Tue, 20 Aug 2013 13:00
Tue, 20 Aug 2013 14:00
Debbie Hull <[email protected]>
Tue, 27 Aug 2013 12:01
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