Assessing respiratory impedance (Zrs) in ventilated patients over a wide frequency band, ranging from breathing rates to typical forced oscillation frequencies, during end-expiratory pauses at different positive end-expiratory pressures (PEEP) is of potential interest to assess a patient's respiratory mechanics. Zrs measurements under these conditions are not possible with the present variants of the forced oscillation technique. The aim of this work was to design a forced oscillation generator operating from spontaneous breathing frequencies whilst withstanding PEEP. To this end, we constructed a generator based on a servocontrolled loudspeaker. This allowed the loudspeaker cone to remain at its resting position regardless of the external PEEP applied. The system was optimized by using a mechanical analogue. The clinical applicability of the servocontrolled generator was assessed by measuring Zrs in mechanically-ventilated chronic obstructive pulmonary disease (COPD) patients during end-expiratory pauses at different transrespiratory pressures. The forced oscillation generator designed may be easily applicable in practice since it is small and light. The system is able to withstand transrespiratory pressures of up to 17 hPa and allows the application of forced oscillation of sufficient amplitude ( > 2 hPa peak-to-peak, 0.25-26 Hz) to obtain reliable respiratory resistance and reactance data. The servocontrolled generator permits the assessment of respiratory mechanics over a wide frequency band ranging from breathing frequencies to the most typical forced oscillation frequencies during end-expiratory pauses at PEEPs within the conventional range.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1183/09031936.95.08071222 | DOI Listing |
ERJ Open Res
November 2024
Ludwig Boltzmann Institute for Lung Health, Vienna, Austria.
Background: Oscillometry devices allow quantification of respiratory function at tidal breathing but device-specific reference equations are scarce: the present study aims to create sex-specific oscillometric reference values for children and adolescents using the Resmon PRO FULL device.
Methods: Healthy participants (n=981) aged 6 to 17 years of the Austrian LEAD general population cohort were included. Subjects had normal weight (body mass index ≤99th percentile) and normal lung volumes (total lung capacity (TLC) ≥ lower limit of normal).
Pediatr Pulmonol
December 2024
Women and Children's Health, School of Life Course Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK.
Background: There has been conflicting evidence regarding the impact of mode of delivery on respiratory outcomes in later childhood and adulthood. It is possible labor status, rather than mode of delivery, influences later respiratory morbidity. We hypothesized that extremely premature infants born to mothers in labor would have better lung function at follow-up than those born to mothers not in labor.
View Article and Find Full Text PDFJ Thorac Dis
November 2024
Department of Respiratory Medicine, Alfred Hospital, Melbourne, Australia.
Background: The incidence of silicosis has increased due to occupational silica exposure from artificial stone, with no treatments proven to halt or reverse the disease. Whole lung lavage (WLL) involves the instillation of fluid into the lungs to wash out silica particles and disease-causing inflammatory cells. This study aimed to determine the feasibility, safety, and possible benefit of WLL in patients with artificial stone silicosis.
View Article and Find Full Text PDFChaos
December 2024
Departamento de Física, Universidade Federal de São Paulo (UNIFESP), Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Câmpus de Diadema, R. São Nicolau 210, 09913-030 Diadema, SP, Brazil.
We report the peculiar organization of oscillations in the forced Brusselator system, found in the parameter space as a nested structure of regular and chaotic phases. To this end, we apply the winding number concept, conceived for nonlinear driven oscillators, to expose all oscillatory phases in the nested structure. First, we use the period and torsion of orbits to describe every periodic oscillation in the parameter spaces, describing the nested structure in high-resolution phase diagrams.
View Article and Find Full Text PDFThe current state-of-the-art climate models when combined together suggest that the anthropogenic weakening of the Atlantic Meridional Overturning Circulation (AMOC) has already begun since the mid-1980s. However, continuous direct observational records during the past two decades have shown remarkable resilience of the AMOC. To shed light on this apparent contradiction, here we attempt to attribute the interdecadal variation of the historical AMOC to the anthropogenic and natural signals, by analyzing multiple climate and surface-forced ocean model simulations together with direct observational data.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!