scholarly journals Measurement of tidal breathing flows in infants using impedance pneumography

2016 ◽  
Vol 49 (2) ◽  
pp. 1600926 ◽  
Author(s):  
Leo Pekka Malmberg ◽  
Ville-Pekka Seppä ◽  
Anne Kotaniemi-Syrjänen ◽  
Kristiina Malmström ◽  
Merja Kajosaari ◽  
...  
Keyword(s):  
Lung Function ◽  
Tidal Flow ◽  
Mean Deviation ◽  
Flow Volume ◽  
Tidal Breathing ◽  
Impedance Pneumography ◽  
Similar Association ◽  
Residual Capacity ◽  
The Mean ◽  
Airway Conductance

Tidal breathing flow volume (TBFV) profiles have been used to characterise altered lung function. Impedance pneumography (IP) is a novel option for assessing TBFV curves noninvasively. The aim of this study was to extend the application of IP for infants and to estimate the agreement between IP and direct pneumotachograph (PNT) measurements in assessing tidal airflow and flow-derived indices.Tidal flow profiles were recorded for 1 min simultaneously with PNT and uncalibrated IP at baseline in 44 symptomatic infants, and after methacholine-induced bronchoconstriction in a subgroup (n=20).The agreement expressed as the mean deviation from linearity ranged between 3.9 and 4.3% of tidal peak inspiratory flow, but was associated with specific airway conductance (p=0.002) and maximal flow at functional residual capacity (V′maxFRC) (p=0.004) at baseline. Acute bronchoconstriction induced by methacholine did not significantly affect the agreement of IP with PNT. TBFV indices derived from IP were slightly underestimated compared to PNT, but were equally well repeatable and associated with baseline V′maxFRC (p=0.012 and p=0.013, respectively).TBFV profiles were consistent between IP and PNT in most infants, but the agreement was affected by reduced lung function. TBFV parameters were not interchangeable between IP and PNT, but had a similar association with lung function in infants.

Tidal breathing flow measurement in awake young children by using impedance pneumography

2013 ◽  
Vol 115 (11) ◽  
pp. 1725-1731 ◽  
Author(s):  
Ville-Pekka Seppä ◽  
Anna S. Pelkonen ◽  
Anne Kotaniemi-Syrjänen ◽  
Mika J. Mäkelä ◽  
Jari Viik ◽  
...  
Keyword(s):  
Young Children ◽  
Flow Measurement ◽  
Intraclass Correlation ◽  
Challenge Test ◽  
Tidal Flow ◽  
Mean Deviation ◽  
Bronchial Obstruction ◽  
Tidal Breathing ◽  
Direct Flow ◽  
Impedance Pneumography

Characteristics of tidal breathing (TB) relate to lung function and may be assessed even in young children. Thus far, the accuracy of impedance pneumography (IP) in recording TB flows in young children with or without bronchial obstruction has not been evaluated. The aim of this study was to evaluate the agreement between IP and direct flow measurement with pneumotachograph (PNT) in assessing TB flow and flow-derived indices relating to airway obstruction in young children. Tidal flow was recorded for 1 min simultaneously with IP and PNT during different phases of a bronchial challenge test with methacholine in 21 wheezy children aged 3 to 7 years. The agreement of IP with PNT was found to be excellent in direct flow signal comparison, the mean deviation from linearity ranging from 2.4 to 3.1% of tidal peak inspiratory flow. Methacholine-induced bronchoconstriction or consecutive bronchodilation induced only minor changes in the agreement. Between IP and PNT, the obstruction-related tidal flow indices were equally repeatable, and agreement was found to be high, with intraclass correlation coefficients for TPTEF/ TE, VPTEF/ VE, and parameter S being 0.94, 0.91, and 0.68, respectively. Methacholine-induced changes in tidal flow indices showed significant associations with changes in mechanical impedance of the respiratory system assessed by the oscillometric technique, with the highest correlation found in VPTEF/ VE ( r = −0.54; P < 0.005 and r = −0.55; P < 0.005 by using IP or PNT, respectively). The results indicate that IP can be considered as a valid method for recording tidal airflow profiles in young children with wheezing disorders.

scholarly journals Tidal breathing flow volume profiles during sleep in wheezing infants measured by impedance pneumography

2019 ◽  
Vol 126 (5) ◽  
pp. 1409-1418 ◽  
Author(s):  
Javier Gracia-Tabuenca ◽  
Ville-Pekka Seppä ◽  
Milla Jauhiainen ◽  
Anne Kotaniemi-Syrjänen ◽  
Kristiina Malmström ◽  
...  
Keyword(s):  
Lung Function ◽  
Airway Obstruction ◽  
Eye Movement ◽  
Rapid Eye Movement ◽  
Flow Volume ◽  
Tidal Breathing ◽  
Sleep Phase ◽  
Asthma Risk ◽  
Impedance Pneumography ◽  
At Home

Overnight analysis of tidal breathing flow volume (TBFV) loops, recorded by impedance pneumography (IP), has been successfully applied in the home monitoring of children with wheezing disorders. However, little is known on how sleep physiology modifies the relationship between TBFV profiles and wheeze. We studied such interactions in wheezing infants. Forty-three infants recruited because of recurrent lower airway symptoms were divided into three groups based on their risk of asthma: high (HR), intermediate (IR), or low (LR). Sedated patients underwent infant lung function testing including assessment of airway responsiveness to methacholine at the hospital and a full-night recording of TBFV profiles at home with IP during natural sleep. Overnight TBFV indexes were estimated from periods of higher and lower respiration variability, presumably belonging to active [rapid eye movement (REM)] and quiet [non-REM (NREM)] sleep, respectively. From 35 valid recordings, absolute time indexes showed intrasubject sleep phase differences. Peak flow relative to time and volume was lower in HR compared with LR only during REM, suggesting altered expiratory control. Indexes estimating the concavity/convexity of flow decrease during exhalation suggested limited flow during passive exhale in HR compared with IR and LR, similarly during NREM and REM. Moreover, during REM convexity was negatively correlated with maximal flow at functional residual capacity and methacholine responsiveness. We conclude that TBFV profiles determined from overnight IP recordings vary because of sleep phase and asthma risk. Physiological changes during REM, most likely decrease in respiratory muscle tone, accentuate the changes in TBFV profiles caused by airway obstruction. NEW & NOTEWORTHY Impedance pneumography was used to investigate overnight tidal breathing flow volume (TBFV) indexes and their interactions with sleep phase [rapid eye movement (REM) vs. non-REM] at home in wheezing infants. The study shows that TBFV indexes vary significantly because of sleep phase and asthma risk of the infant and that during REM the changes in TBFV indexes caused by airway obstruction are accentuated and better associated with lung function of the infant.

Comparison of glottic areas measured by acoustic reflections vs. computerized tomography

1988 ◽  
Vol 64 (1) ◽  
pp. 367-370 ◽  
Author(s):  
A. D. D'Urzo ◽  
I. Rubinstein ◽  
V. G. Lawson ◽  
K. P. Vassal ◽  
A. S. Rebuck ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Linear Regression Analysis ◽  
Acoustic Method ◽  
Ct Scans ◽  
Tidal Breathing ◽  
Acoustic Reflection ◽  
Acoustic Technique ◽  
Residual Capacity ◽  
Equivalent Area ◽  
The Mean

We compared measurements of glottic area obtained by acoustic reflection technique with anatomically equivalent area measured from computerized tomographic (CT) scans of the neck in 11 subjects with glottic pathology. Both measurements were performed in the supine position during tidal breathing at functional residual capacity. We found excellent agreement in glottic areas obtained by both methods: the mean (+/- SD) values were 1.8 +/- 0.8 cm2 for the acoustic method and 1.7 +/- 0.9 cm2 for the CT method. Linear regression analysis revealed the following relationship between the area measured by acoustic technique (AAC) and that measured by CT (ACT): AAC = 0.81.ACT + 0.36. There was a significant correlation between the two measurements of glottic area (r = 0.95, P less than 0.0001). We conclude that the acoustic reflection technique may be used reliably in clinical and physiological studies concerned with glottic geometry.

Airway reactivity in infants: a positive response to methacholine and metaproterenol

1987 ◽  
Vol 62 (3) ◽  
pp. 1155-1159 ◽  
Author(s):  
R. S. Tepper
Keyword(s):  
Challenge Test ◽  
Threshold Concentration ◽  
Base Line ◽  
Tidal Breathing ◽  
Airway Reactivity ◽  
Bronchial Smooth Muscle ◽  
Bronchial Challenge ◽  
Control Value ◽  
Residual Capacity ◽  
The Mean

Because the presence of bronchial smooth muscle reactivity in infants remains controversial, airway reactivity was assessed in 10 normal, asymptomatic male infants less than 15 mo of age by measuring the changes that occurred in the maximal expiratory flows at functional residual capacity (VmaxFRC) during a methacholine bronchial challenge test. Sleeping infants inhaled doubling concentrations of methacholine by 2 min of tidal breathing, starting with a concentration of 0.075 mg/ml, and the bronchial challenge was stopped when VmaxFRC decreased by at least 40%. The threshold concentration of methacholine required to produce a decrease in VmaxFRC by 2 SD's of the control value was 0.43 mg/ml (0.11–0.90). By a methacholine concentration of 1.2 mg/ml, all infants decreased VmaxFRC by at least 40% (range 40–75%), and the mean dose required to produce a 40% decrease was 0.72 mg/ml. The airway reactivity was not related to base-line flows. During the methacholine challenge, no infant developed wheezing, but the percent oxygen saturation for the group decreased significantly (P less than 0.05) from 94 to 92%. Following the methacholine, the infants inhaled the bronchodilator metaproterenol, and 10 min later, VmaxFRC returned to base line. This study demonstrates that infants exhibit airway reactivity as evidenced by bronchoconstriction with methacholine and the subsequent bronchodilation with metaproterenol.

Pulmonary mechanics during exercise in subjects with chronic airflow obstruction

1980 ◽  
Vol 49 (3) ◽  
pp. 511-515 ◽  
Author(s):  
D. G. Stubbing ◽  
L. D. Pengelly ◽  
J. L. Morse ◽  
N. L. Jones
Keyword(s):  
Tidal Flow ◽  
Airflow Obstruction ◽  
Maximum Flow ◽  
Transpulmonary Pressure ◽  
Pulmonary Mechanics ◽  
Flow Volume ◽  
Tidal Breathing ◽  
Flow Rates ◽  
Control Value ◽  
Expiratory Flow

A body plethysmograph was used to measure pulmonary mechanics in six subjects with chronic airflow obstruction during steady states at rest and during exercise at 200 and 400 kpm . min-1. The mean forced expired volume in 1 s was 1.32 liters (39.2% predicted). The flow rates during tidal breathing reached the maximum expiratory flow-volume (MEFV) curve in all but one subject, and on exercise they all reached the MEFV curve. Total lung capacity did not change significantly, but functional residual capacity increased to 104% of the control value (P less than 0.05) and residual volume increased to 113.3% of the control value (P less than 0.02). The MEFV curves did not change and tidal flow rates in excess of th MEFV curve were not seen. Dynamic compliance fell with increasing exercise to 52.8% (P less than 0.01) and static expiratory pulmonary compliance to 90.2% of the control value. Transpulmonary pressures during tidal breathing when expiratory flow reached the MEFV curve increased to progressively higher values as the work load increased. At low work loads there were several subjects with negative transpulmonary pressure when maximum flow rates were present. In patients with chronic airflow obstruction, little change occurs during exercise in pulmonary mechanics; the tidal flow patterns are dominated by the expired flow-volume curve, which is not changed by exercise; maximum flow occurs in some patients when transpulmonary pressure is still negative.

DFT Benchmark Study of the O--O Bond Dissociation Energy in Peroxides Validated with High-Level Ab-Initio Calculations

2019 ◽  
Author(s):  
Danilo Carmona ◽  
Pablo Jaque ◽  
Esteban Vöhringer-Martinez
Keyword(s):  
Reference Value ◽  
Basis Set ◽  
Basis Sets ◽  
Mean Deviation ◽  
Bond Dissociation ◽  
Dissociation Energies ◽  
The Mean ◽  
Experimental Values ◽  
High Level ◽  
Almost All

<div><div><div><p>Peroxides play a central role in many chemical and biological pro- cesses such as the Fenton reaction. The relevance of these compounds lies in the low stability of the O–O bond which upon dissociation results in radical species able to initiate various chemical or biological processes. In this work, a set of 64 DFT functional-basis set combinations has been validated in terms of their capability to describe bond dissociation energies (BDE) for the O–O bond in a database of 14 ROOH peroxides for which experimental values ofBDE are available. Moreover, the electronic contributions to the BDE were obtained for four of the peroxides and the anion H2O2− at the CBS limit at CCSD(T) level with Dunning’s basis sets up to triple–ζ quality provid- ing a reference value for the hydrogen peroxide anion as a model. Almost all the functionals considered here yielded mean absolute deviations around 5.0 kcal mol−1. The smallest values were observed for the ωB97 family and the Minnesota M11 functional with a marked basis set dependence. Despite the mean deviation, order relations among BDE experimental values of peroxides were also considered. The ωB97 family was able to reproduce the relations correctly whereas other functionals presented a marked dependence on the chemical nature of the R group. Interestingly, M11 functional did not show a very good agreement with the established order despite its good performance in the mean error. The obtained results support the use of similar validation strategies for proper prediction of BDE or other molecular properties by DF Tmethods in subsequent related studies.</p></div></div></div>

Der Sommer und Herbst 2003 aus phänologischer Sicht | Summer and autumn 2003 from a phenological point of view

2004 ◽  
Vol 155 (5) ◽  
pp. 142-145 ◽  
Author(s):  
Claudio Defila
Keyword(s):  
Time Series ◽  
New Record ◽  
Point Of View ◽  
Late Spring ◽  
Mean Deviation ◽  
Leaf Shedding ◽  
The Mean ◽  
Very High ◽  
Selection Of

The record-breaking heatwave of 2003 also had an impact on the vegetation in Switzerland. To examine its influences seven phenological late spring and summer phases were evaluated together with six phases in the autumn from a selection of stations. 30% of the 122 chosen phenological time series in late spring and summer phases set a new record (earliest arrival). The proportion of very early arrivals is very high and the mean deviation from the norm is between 10 and 20 days. The situation was less extreme in autumn, where 20% of the 103 time series chosen set a new record. The majority of the phenological arrivals were found in the class «normal» but the class«very early» is still well represented. The mean precocity lies between five and twenty days. As far as the leaf shedding of the beech is concerned, there was even a slight delay of around six days. The evaluation serves to show that the heatwave of 2003 strongly influenced the phenological events of summer and spring.

Early changes of lung function and structure in an elastase model of emphysema—a hyperpolarized 3He MRI study

2008 ◽  
Vol 104 (3) ◽  
pp. 773-786 ◽  
Author(s):  
Kiarash Emami ◽  
Robert V. Cadman ◽  
John M. Woodburn ◽  
Martin C. Fischer ◽  
Stephen J. Kadlecek ◽  
...  
Keyword(s):  
Lung Function ◽  
Lung Ventilation ◽  
Unit Group ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Entire Lung ◽  
Residual Capacity ◽  
Regional Basis ◽  
Mean Linear Intercept ◽  
Mri Study

Early changes of lung function and structure were studied in the presence of an elastase-induced model of emphysema in 35 Sprague-Dawley rats at mild (5 U/100 g) and moderate (10 U/100 g) severities. Lung ventilation was measured on a regional basis (at a planar resolution of 3.2 mm) by hyperpolarized 3He MRI at 5 and 10 wk after model induction. Subsequent to imaging, average alveolar diameter was measured from histological slices taken from the centers of each lobe. Changes of mean fractional ventilation, mean linear intercept, and intrasubject heterogeneity of ventilation were studied during disease progression. Mean fractional ventilation was significantly different between healthy controls (0.23 ± 0.04) and emphysematous animals at both time points in the 10-unit group (0.06 ± 0.02 and 0.12 ± 0.05, respectively). Changes in average alveolar diameter were not statistically observable until the 10th wk between healthy (37 ± 10 μm) and emphysematous rats (73 ± 25 and 95 ± 31 μm, for 5 and 10 units, respectively). Assessment of function-structure correlation suggested that the majority of the decline in fractional ventilation occurred in the first 5 wk, while enlargement of alveolar diameters appeared primarily between the 5th and 10th wk. A thresholding metric, based on the 20th percentile of fractional ventilation over the entire lung, was utilized to detect the onset of the disease with confidence, independent of whether the regional ventilation measurements were normalized with respect to the delivered tidal volume and estimated functional residual capacity of each individual rat.

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