Tidal forced expirations

Sly, Peter D.; Tepper, Robert S.; Henschen, M.; Gappa, Monika; Stocks, Janet

doi:10.1034/j.1399-3003.2000.16d29.x

Cited by 127 publications

(25 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, lung function was assessed according to standardised protocols using the plethysmographic and rapid thoracoabdominal compression techniques [27,28], and a previously validated method was used to measure airway responsiveness [13]. Even in the measurement of FeNO, efforts were made to standardise flow during sampling of exhaled air by using a modified single breath technique; nonetheless, the results in the current study may have been confounded by ambient and upper airway nitric oxide [29].…”

Section: Discussionmentioning

confidence: 99%

The effect of montelukast on respiratory symptoms and lung function in wheezy infants

Pelkonen¹,

Malmström²,

Sarna³

et al. 2012

Eur Respir J

View full text Add to dashboard Cite

Our aim was to investigate the effectiveness of montelukast in recurrently wheezy infants.We randomised 113, 6-24-month-old children with recurrent wheezing to receive either placebo or montelukast daily for an 8-week period. The primary end-point was symptom-free days. The secondary aims were to evaluate the effect of montelukast on rescue medication, on lung function, airway responsiveness and exhaled nitric oxide fraction (FeNO). Clinical response and FeNO were determined, the functional residual capacity (FRC) and specific airway conductance (sGaw) were measured using an infant whole-body plethysmograph, the maximal flow at functional residual capacity (V9max,FRC) was recorded using the squeeze technique and airway responsiveness was evaluated by performing a dosimetric methacholine challenge test.There was no significant difference in changes in weekly symptom-free days between the montelukast and the placebo group (3.1-3.7 days versus 2.7-3.1 days, p50.965). No significant differences were detected in the secondary end-points, i.e. use of rescue medication, FRC, sGaw, V9max,FRC, FeNO or airway responsiveness between groups.Montelukast therapy did not influence the number of symptom-free days, use of rescue medication, lung function, airway responsiveness or airway inflammation in recurrently wheezy, very young children.

show abstract

Section: Discussionmentioning

confidence: 99%

The effect of montelukast on respiratory symptoms and lung function in wheezy infants

Pelkonen¹,

Malmström²,

Sarna³

et al. 2012

Eur Respir J

View full text Add to dashboard Cite

show abstract

“…4 5 A possible explanation could be that, according to recommendations, V′ maxFRC after bronchodilation is assessed with the same jacket pressure as used before the administration. 16 Possibly, one should assess the lowest pressure at which the highest flows are obtained both before and after β 2 agonist administration.…”

Section: Discussionmentioning

confidence: 99%

“…Equipment and procedures were in accordance with guidelines, in which the RTC technique is described in detail. 16 Mean V′ maxFRC of 3-5 technically acceptable measurements was expressed as Z score. 16 …”

Section: Methodsmentioning

confidence: 99%

Bronchodilation in infants with malacia or recurrent wheeze

Hofhuis

2003

Archives of Disease in Childhood

View full text Add to dashboard Cite

Background: Controversy remains regarding the effectiveness of bronchodilators in wheezy infants. Aims: To assess the effect of inhaled β 2 agonists on lung function in infants with malacia or recurrent wheeze, and to determine whether a negative effect of β 2 agonists on forced expiratory flow (V′ maxFRC ) is more pronounced in infants with airway malacia, compared to infants with wheeze. Methods: We retrospectively analysed lung function data of 27 infants: eight with malacia, 19 with recurrent wheeze. Mean (SD) age was 51 (18) weeks. Mean V′ maxFRC (in Z score) was assessed before and after inhalation of β 2 agonists. Results: Baseline V′ maxFRC was below reference values for both groups. Following inhalation of β 2 agonists the mean (95% CI) change in mean V′ maxFRC in Z scores was −0.10 (−0.26 to 0.05) and −0.33 (−0.55 to −0.11) for the malacia and wheeze group, respectively. Conclusions: In infants with wheeze, inhaled β 2 agonists caused a significant reduction in mean V′ max -

show abstract

“…s -1 , but increase to 0.6 or 1.5 L . s -1 , respectively, if partial or raised lung volume forced expiratory manoeuvres are generated [1,3,12]. The model described in this paper can reproduce given¯ows from 0±1.5 L .…”

Section: Tidal Volume And¯ow Measurementsmentioning

confidence: 88%

The infant lung function model: a mechanical analogue to test infant lung function equipment

2001

View full text Add to dashboard Cite

To facilitate international multicentre studies and quality control of infant pulmonary function measurements, the European Respiratory Society-American Thoracic Society (ERS-ATS) working group for infant lung function testing aims to develop speci®cations for standardized infant lung function equipment and software. However, a standardized test device is also needed to test whether existing infant lung function equipment is able to meet these requirements.The authors have built a "mechanical model baby" consisting of a linear pump which can reproduce prerecorded tidal¯ow waveforms with a precision of 0.5% (full stroke), enabling the simulation of tidal and forced¯ow patterns. This linear pump can be connected to a series of copper lung volumes (range 50±300 mL) with known time constants, so that lung volumes can be reproduced with a precision of 1% at frequencies 10±120 bpm. Five air¯ow resistors were built using sinter material.When assessed using¯ows 0±300 mL . s -1 all resistors showed a quasilinear pressure/ ow relationship, with slopes 1.0±5.6 kPa . L -1 . s. These resistances could be reproduced with a precision of 2.5%. The infant lung model can also be used to assess frequency responses of infant lung function equipment, since the pump is capable of delivering low amplitude volumes up to 20 Hz in a pseudorandom noise manner.In summary, based on error estimations, this infant lung model is able to test whether or not infant lung function equipment meets the requirements suggested by the European Respiratory Society-American Thoracic Society standardization group, that is:¯ow measurements within 2.5%, volume and resistance measurements within 5%, frequency response: magnitude attenuation <10% and phase shift <3 degrees at 10 Hz. Lung function measurements in the ®rst year of life have had an increasing impact on the understanding of normal lung development and on the early detection and monitoring of lung disease. Several lung function techniques have been proposed to access the highly complex mechanical properties of the infant lung [1]. In order to assess infant lung mechanics, it is necessary to measure resistance, lung volumes and both tidal and forced¯ow patterns with a high degree of accuracy. Assessment of lung mechanics in infants requires higher technical demands of the equipment than when studying adults, because of a smaller signal to noise ratio and higher respiratory frequency. Furthermore, calibration of equipment is often performed under highly specialized conditions, while the overall performance of the equipment as an integrated whole is rarely assessed. Hand held calibration syringes do not allow maintenance of a constant pumping frequency and the air within them is subject to warming by the investigator9s hand. Consequently, the thermal behaviour of these syringes is both unknown and highly variable.It is recognized that automated calibration and equipment testing procedures are potentially superior to manual approaches, and some manufacturers now provide semiautomatic calibra...

show abstract

Tidal forced expirations

Cited by 127 publications

References 13 publications

The effect of montelukast on respiratory symptoms and lung function in wheezy infants

The effect of montelukast on respiratory symptoms and lung function in wheezy infants

Bronchodilation in infants with malacia or recurrent wheeze

The infant lung function model: a mechanical analogue to test infant lung function equipment

Contact Info

Product

Resources

About