Laryngeal resistance immediately after panting in control and constricted airways

1985 ◽  
Vol 58 (4) ◽  
pp. 1164-1169 ◽  
Author(s):  
K. Sekizawa ◽  
H. Sasaki ◽  
T. Takishima
Keyword(s):  
Forced Oscillation ◽  
Low Frequency ◽  
Normal Subjects ◽  
Forced Oscillation Technique ◽  
Respiratory Resistance ◽  
Frequency Sound ◽  
Laryngeal Resistance ◽  
Control State

Laryngeal resistance (Rla) in the postpanting interval (PPRla) was examined in five normal subjects in the control state and with methacholine- and histamine-induced bronchoconstriction. Respiratory resistance (Rrs) was measured by the forced oscillation technique at 10 Hz, and Rla was measured by the low-frequency sound method (Sekizawa, K., C. Shindoh, W. Hida, S. Suzuki, et al. J. Appl. Physiol. 55:591–597, 1983). Inspiratory Rrs (IRrs) was lower than expiratory Rrs (ERrs), and Rrs immediately after panting (PPRrs) was not significantly different from IRrs in the three airway conditions. Rla increased with bronchoconstriction and inspiratory Rla (IRla) was lower than expiratory Rla (ERla). PPRla was lower than IRla (P less than 0.01) by an amount corresponding to the decrease in Rrs in the control airway. However, in constricted airways, PPRla was higher than IRla and about the same as ERla. We suggest that the panting maneuver is suitable for minimizing the effect of laryngeal artifact in the control airway, but in the constricted airway the panting maneuver may fail to cause widening of the laryngeal orifice.

Effect of a previous voluntary deep breath on laryngeal resistance in normal and asthmatic subjects

1987 ◽  
Vol 63 (4) ◽  
pp. 1406-1412 ◽  
Author(s):  
K. Sekizawa ◽  
M. Yanai ◽  
H. Sasaki ◽  
T. Takishima
Keyword(s):  
Bronchial Asthma ◽  
Forced Oscillation ◽  
Low Frequency ◽  
Normal Subjects ◽  
Base Line ◽  
Respiratory Resistance ◽  
Deep Breath ◽  
Airway Response ◽  
Methacholine Provocation ◽  
Laryngeal Resistance

We studied changes in both laryngeal resistance (Rla) and respiratory resistance (Rrs) after a voluntary deep breath in 7 normal and 20 asthmatic subjects. Rla was measured using a low-frequency sound method (Sekizawa et al. J. Appl. Physiol. 55: 591–597, 1983) and Rrs by forced oscillation at 3 Hz. In normal subjects, both Rla and Rrs significantly decreased after a voluntary deep breath (0.05 less than P less than 0.01). During methacholine provocation in the normal subjects, a voluntary deep breath significantly decreased Rrs (0.05 less than P less than 0.01, but Rla was significantly increased (0.05 less than P less than 0.01). In 10 asthmatic subjects in remission, a voluntary deep breath significantly increased Rrs (0.05 less than P less than 0.01) but significantly decreased Rla (0.05 less than P less than 0.01). In another 10 asthmatic subjects during spontaneous mild attacks, a voluntary deep breath significantly increased both Rrs and Rla (0.05 less than P less than 0.01). The present study showed that without obvious bronchoconstriction, Rla decreased after a voluntary deep breath in both normal and asthmatic subjects but, with bronchoconstriction, Rla increased in both groups. Subtraction of the change in Rla from Rrs gives the change in Rrs below the larynx (Rlow). Rlow changed little or decreased in normal subjects and increased in asthmatic subjects, irrespective of base-line bronchomotor tone. These results suggest that airway response below the larynx after a voluntary deep breath differentiates patients with bronchial asthma from normal subjects.

Control of larynx during loaded breathing in normal subjects

1986 ◽  
Vol 60 (6) ◽  
pp. 1887-1893 ◽  
Author(s):  
K. Sekizawa ◽  
M. Yanai ◽  
H. Sasaki ◽  
T. Takishima
Keyword(s):  
Low Frequency ◽  
Normal Subjects ◽  
Respiratory Center ◽  
External Resistance ◽  
Frequency Sound ◽  
Tightly Coupled ◽  
Loaded Breathing ◽  
Laryngeal Resistance

We examined laryngeal resistance (Rla) in six normal subjects in control and four kinds of loaded breathing: hypercapnia, chest strapping, added external resistance, and inhaled methacholine. Rla was measured with a low-frequency sound methed (Sekizawa et al., J. Appl. Physiol. 55: 591–597, 1983). In control and the four kinds of loaded breathing, changes in Rla were tightly coupled with ventilation and Rla decreased during inspiration and increased during expiration. Hypercapnia and chest strapping significantly decreased Rla in both inspiration and expiration in all subjects. Added external resistance decreased inspiratory Rla in all subjects, but decreased expiratory Rla in three subjects, did not change it in two subjects, and increased it in one subject. Inhaled methacholine increased Rla in both inspiration and expiration in all subjects. The present study suggests that although laryngeal movement is tightly coupled with ventilation, laryngeal aperture may be determined by the complex competition of dilating and constricting mechanisms associated with the activity of the respiratory center and neural reflexes from the airway.

scholarly journals Impact of lung disease on respiratory impedance in young children with cystic fibrosis

2015 ◽  
Vol 46 (6) ◽  
pp. 1672-1679 ◽  
Author(s):  
Kathryn A. Ramsey ◽  
Sarath C. Ranganathan ◽  
Catherine L. Gangell ◽  
Lidija Turkovic ◽  
Judy Park ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Preschool Children ◽  
Lung Disease ◽  
Forced Oscillation ◽  
Forced Oscillation Technique ◽  
Respiratory Resistance ◽  
Lung Abnormalities ◽  
Respiratory Inflammation ◽  
Function Testing ◽  
Tomography Scan

This study aimed to evaluate the ability of the forced oscillation technique (FOT) to detect underlying lung disease in preschool children with cystic fibrosis (CF) diagnosed following newborn screening.184 children (aged 3–6 years) with CF underwent lung function testing on 422 occasions using the FOT to assess respiratory resistance and reactance at the time of their annual bronchoalveolar lavage collection and chest computed tomography scan. We examined associations between FOT outcomes and the presence and progression of respiratory inflammation, infection and structural lung disease.Children with CF who had pronounced respiratory disease, including free neutrophil elastase activity, infection with pro-inflammatory pathogens and structural lung abnormalities had similar FOT outcomes to those children without detectable lung disease. In addition, the progression of lung disease over 1 year was not associated with worsening FOT outcomes.We conclude that the forced oscillation technique is relatively insensitive to detect underlying lung disease in preschool children with CF. However, FOT may still be of value in improving our understanding of the physiological changes associated with early CF lung disease.

The Reliability of Respiratory Resistance Measured by the Forced Oscillation Technique

1986 ◽  
Vol 71 (s15) ◽  
pp. 8P-9P
Author(s):  
J.E. Neild ◽  
C.H.C. Twort ◽  
S. Chinn ◽  
S. McCormack ◽  
P.G.J. Burney ◽  
...  
Keyword(s):  
Forced Oscillation ◽  
Forced Oscillation Technique ◽  
Respiratory Resistance

The effect of verapamil and inspired CO2 on the bronchoconstriction provoked by hyperventilation in normal humans

1985 ◽  
Vol 69 (3) ◽  
pp. 361-364 ◽  
Author(s):  
C. H. C. Twort ◽  
J. E. Neild ◽  
I. R. Cameron
Keyword(s):  
Co2 Concentration ◽  
Normal Subjects ◽  
Specific Conductance ◽  
Forced Oscillation Technique ◽  
Respiratory Resistance ◽  
Voluntary Hyperventilation ◽  
Before And After ◽  
Normal Humans ◽  
End Tidal ◽  
Oral Verapamil

1. Two groups of eight normal subjects were investigated in separate studies to demonstrate the effects of changes in end-tidal Pco2, and of pretreatment with the calcium antagonist drug verapamil, on bronchoconstriction provoked by voluntary hyperventilation. 2. Total respiratory resistance (Ros) was measured by the forced oscillation technique before and after 90s voluntary hyperventilation. End-tidal Pco2 during hyperventilation was varied by altering inspired CO2 concentration. When end-tidal Pco2 fell during hyperventilation, there was a rise in Ros. This did not occur if end-tidal Pco2 was controlled at a normal resting level during hyperventilation. 3. Specific conductance (sGaw) was measured before and after 90 s voluntary hyperventilation of air. Subjects were treated with oral verapamil or placebo for 2 1/2 days and the effect of hyperventilation on sGaw was reassessed. Verapamil reduced significantly the fall in sGaw caused by hyperventilation. Placebo had no effect. 4. In normal humans, bronchoconstriction provoked by hyperventilating air at ambient temperature and humidity is mediated by the fall in Pco2, and is also reduced by verapamil.

Respiratory resistance by end-inspiratory occlusion and forced oscillations in intubated patients

1996 ◽  
Vol 80 (4) ◽  
pp. 1105-1111 ◽  
Author(s):  
L. Beydon ◽  
P. Malassine ◽  
A. M. Lorino ◽  
C. Mariette ◽  
F. Bonnet ◽  
...  
Keyword(s):  
Forced Oscillation ◽  
Forced Oscillations ◽  
Forced Oscillation Technique ◽  
Respiratory Impedance ◽  
Respiratory Resistance ◽  
Airway Occlusion ◽  
Residual Capacity ◽  
Occlusion Technique ◽  
Air Compression ◽  
Good Agreement

Measurement of respiratory impedance by the forced oscillation technique (FOT) in intubated patients requires corrections for the flow-dependent resistance, inertance, and air compression inside the endotracheal tube (ETT). Recently, we published a method to correct respiratory impedance for the mechanical contribution of the ETT. To validate this correction, we compared the respiratory resistance obtained with this method (Rfo) to the intrinsic (Rmin) and total resistances (RT) measured by the airway-occlusion technique (OCT) in 16 intubated sedated paralyzed ventilated patients. The FOT was applied at functional residual capacity in the 4- to 32-Hz frequency range, whereas the OCT was performed at the end of a normal constant-flow inspiration. Rmin corrected with Rfo measured at 16 and 32 Hz [Rfo(16) = 1.10 x Rmin + 0.10 cmH2O.s.l-1, r = 0.96, P < 0.001; Rfo(32) = 0.93 x Rmin + 0.72 cmH2O.s.l-1, r = 0.97, P < 0.001]. RT corrected with Rfo at 4 Hz [Rfo(4) = 1.11 x RT - 1.48 cmH2O.s.l-1; = 0.92; P < 0.001]. We conclude that the FOT improved by correction for the behavior of the ETT is in good agreement with the OCT in intubated patients.

A modified measurement of respiratory resistance by forced oscillation during normal breathing

1975 ◽  
Vol 39 (2) ◽  
pp. 305-311 ◽  
Author(s):  
D. C. Stanescu ◽  
R. Fesler ◽  
C. Veriter ◽  
A. Fans ◽  
L. Brasseur
Keyword(s):  
Flow Rate ◽  
Respiratory System ◽  
Obstructive Lung Disease ◽  
Forced Oscillation ◽  
Forced Oscillation Technique ◽  
Good Reproducibility ◽  
Respiratory Resistance ◽  
Normal Breathing ◽  
Respiratory Flow ◽  
Mouth Pressure

We have modified the measurements of the resistance of the respiratory system, Rrs, by the forced oscillation technique and we have developed equipment to automatically compute Rrs. Flow rate and mouth pressure are treated by selective averaging filters that remove the interference of the subject's respiratory flow on the imposed oscillations. The filtered mean Rrs represents a weighted ensemble average computer over both inspiration and expiration. This method avoids aberrant Rrs values, decreases the variability, and yields an unbiased mean Rrs. Rrs may be measured during slow or rapid spontaneous breathing, in normals and in obstructive patients, over a range of 3–9 Hz. A good reproducibility of Rrs at several days' interval was demonstrated. Frequency dependence of Rrs was found in patients with obstructive lung disease but not in healthy nonsmokers.

The repeatability and validity of respiratory resistance measured by the forced oscillation technique

1989 ◽  
Vol 83 (2) ◽  
pp. 111-118 ◽  
Author(s):  
J.E. Neild ◽  
C.H.C. Twort ◽  
S. Chinn ◽  
S. McCormack ◽  
T.D. Jones ◽  
...  
Keyword(s):  
Forced Oscillation ◽  
Forced Oscillation Technique ◽  
Respiratory Resistance

A modified forced oscillation technique for measurements of respiratory resistance

1977 ◽  
Vol 42 (4) ◽  
pp. 650-655 ◽  
Author(s):  
H. Aronsson ◽  
L. Solymar ◽  
J. Dempsey ◽  
J. Bjure ◽  
T. Olsson ◽  
...  
Keyword(s):  
Forced Oscillation ◽  
Signal To Noise Ratio ◽  
Optimization Technique ◽  
Forced Oscillation Technique ◽  
Respiratory Resistance ◽  
Asthmatic Children ◽  
The Difference ◽  
Resistance Value ◽  
Automated Determination

We present a modification of forced oscillation technique for automated determination of total respiratory resistance during inspiration. The modifications consist of a computerized signal averaging and an optimization technique in the assessment of the resistance value. Thereby a favorable signal-to-noise ratio is obtained, allowing very low superimposed pressure oscillations. The method is validated by comparison with a conventional esophageal balloon method, by estimating added mechanical resistances in healthy subjects and by measuring the effect of bronchodilation in asthmatic children. The coefficient of variation as obtained from day-to-day measurements was about 7%. Mechanical resistances, estimated as the difference in total resistance with and without external resistance, were within 7% of their values determined for the resistances alone. A significant decrease in resistance was obtained in each of the asthmatic children following bronchodilation.

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