Glottis opening and airway resistance.

Stănescu, Dan; Clement, J. L.; J, Pattijn; Woestijne, K. P. Van de

doi:10.1152/jappl.1972.32.4.460

Cited by 102 publications

(41 citation statements)

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“…Pmo may be measured during inspiration or expiration. In this study, Pmo was measured during inspiration, as differences in glottic opening are more likely to affect measurements during expiration [16]. Several principles have been suggested for estimating the alveolar pressure from the Pmo recording [17].…”

Section: Rintmentioning

confidence: 99%

Lung function measurement in awake young children

Bisgaard¹,

Klug²

1995

Eur Respir J

252

208

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Keywords: interrupter lung function oscillometry spirometry transcutaneous measurements of oxygen whole body plethysmography young children Received: December 14 1994 Accepted after revision August 28 1995 This study was supported by grants from the Danish Ministry of Health and from Astra-Draco, Lund, Sweden.Eur Respir J, 1995, 8, 2067-2075 DOI: 10.1183 ) were compared with concomitant measurements of specific airway resistance (sRaw) and forced expiratory volume in one second (FEV1) by whole body plethysmography and spirometry, respectively, during methacholine challenge in 21 young children aged 4-6 yrs, with suspected asthma. Measurements with each technique were repeated after each challenge step. A special face-mask was developed with an integrated mouthpiece which ensured mouth breathing during the measurements.The order of sensitivity of the techniques to assess methacholine-induced changes in lung function was ZIOS > sRaw > Ptc,O 2 > FEV1 > Rint. ZIOS was significantly more sensitive than all subsequent methods, and Ptc,O 2 was significantly more sensitive than FEV1. ZIOS, sRaw and Rint, but not Ptc,O 2 and FEV1, detected the subclinical increase in bronchial muscle tone in the children during baseline, which was revealed by the significantly reduced airway obstruction after inhalation of a b b b b b 2 -agonist as compared to baseline.It is concluded that ZIOS, Rint and Ptc,O 2 change in parallel with sRaw and FEV1 and with a comparable sensitivity during simultaneous measurements of the response to methacholine in young children aged 4-6 yrs. This implies that ZIOS, Rint and Ptc,O 2 provide convenient indices of changes in lung function. Their combined use will be useful for monitoring airway diseases of young children.

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Section: Rintmentioning

confidence: 99%

Lung function measurement in awake young children

Bisgaard¹,

Klug²

1995

Eur Respir J

252

208

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“…Moreover, Raw* and Raw,pleth are measured at different frequencies and under different conditions of breathing pattern and airway flow. The panting manoeuvre produces larger flow, hence larger resistance value, than quiet breathing, but this is probably cancelled by the fact that panting also increases the glottic aperture [11].…”

Section: Discussionmentioning

confidence: 99%

Separation of airway and tissue properties by transfer respiratory impedance and thoracic gas volume in reversible airway obstruction

Marchal¹,

Bouaziz²,

Baeyert³

et al. 1996

Eur Respir J

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The aim of this study was to establish the ability to estimate separate airway and tissue properties from transfer respiratory impedance (Zrs,tr) data in the presence of airway obstruction.Zrs,tr, thoracic gas volume (TGV) and airway resistance (Raw,pleth) were measured in the presence of obstruction and after use of a bronchodilator (BD) in 13 normal or asymptomatic asthmatic adults and 28 children with symptomatic asthma. An analytical approach was used to solve the equations of a simplified variant of DuBois' model, including airway resistance (Raw*) and inertance (Iaw), tissue compliance (Ct) and resistance (Rt) and pulmonary gas compliance (Cg).The equations of the model could not be reliably solved in four children before BD. Mean Raw,pleth was not different from mean Raw* in adults before (mean±SEM) (3.4±0.5 vs 3.1±0.3 hPa·s·L -1 ) or after BD (1.4±0.2 vs 1.8±0.2 hPa·s·L -1 ), or in children after BD (2.9±0.3 vs 3.2±0.2 hPa·s·L -1 , respectively). In children before BD, Raw* was significantly underestimated compared with Raw,pleth (3.8±0.4 vs 5.4±0.6 hPa·s·L -1 ). Overall, a significant positive correlation was found between the difference [Raw,pleth -Raw*] and Raw,pleth (r=0.82). In adults, BD induced a decrease in Raw* and Rt, an increase in Ct, and no change in Iaw. In children after BD, there was no significant change in Raw* or Ct, whilst Rt decreased and Iaw increased.Taking Raw,pleth as the gold standard, it is concluded that coherent estimation of parameters of DuBois' model may be obtained from combined Zrs,tr and TGV measurements in normal subjects and moderately obstructed adults, but not in children with significant airway obstruction. This seems to be due to the systematic underestimation of Raw*. Eur Respir J., 1996, 9, 253-261 Respiratory input impedance (Zrs,in) measured by the forced oscillation technique is becoming increasingly popular in lung function testing, and provides a convenient, noninvasive estimation of respiratory system resistive and reactive properties. Another interesting approach is to obtain the transfer impedance of the respiratory system (Zrs,tr) by varying pressure at the chest wall and measuring flow at the mouth. The advantage of this technique is twofold. Firstly, pressure variations in the pneumotachograph are small and the accuracy of flow measurement at high frequency does not critically depend on the symmetry of the flow channel. This is particularly important when large resistances are to be measured [1], which is the case of children with airway obstruction. Secondly, Zrs,tr is significantly influenced by pulmonary gas compressibility (Cg) described in DuBois' model [2].The parameters of airway and tissue impedance were estimated from Zrs,tr in normal adult humans, using Cg value provided by thoracic gas volume (TGV) measurement [3]. With comparative measurements of Zrs,in and Zrs,tr it was found that the second, but not the first, approach could provide a correct estimation of airway and tissue parameters [4]. It was also shown in healthy dogs and ...

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“…In normal subjects upper airway resistance falls slightly as respiratory frequency is increased (Spann & Hyatt, 1971) and as panting volume is reduced (Stanescu et al, 1972) the latter probably because of reduced turbulence. However, when panting was compared to quiet breathing in the body plethysmograph there was no difference in Raw in normal subjects ) though a small reduction (12%) was seen in patients with chronic bronchitis similar to that seen in a similar group of patients by Barter & Campbell (1973).…”

Section: Body Plethysmographymentioning

confidence: 99%

“…The technique of the subject may be important since panting has been shown to reduce the difference in Raw between inspiration and expiration (Stanescu et al, 1972) and repeated measurements may lead to a training effect with improved reproducibility .…”

Section: Body Plethysmographymentioning

confidence: 99%