A comparison of interrupter and forced oscillation measurements of respiratory resistance in the dog

1992 ◽  
Vol 72 (1) ◽  
pp. 46-52 ◽  
Author(s):  
J. H. Bates ◽  
B. Daroczy ◽  
Z. Hantos
Keyword(s):  
Respiratory System ◽  
High Frequency ◽  
Forced Oscillation ◽  
Forced Oscillation Technique ◽  
Respiratory Resistance ◽  
Modest Contribution ◽  
Flow Interruption ◽  
Tracheal Pressure ◽  
Airways Resistance ◽  
Respiratory System Resistance

We compared the values of resistance produced by the forced oscillation technique (FOT) and the flow interruption technique (IT) when applied to six anesthetized paralyzed tracheostomized dogs. The FOT returned values of respiratory system resistance as a function of frequency [Re(f)] between 0.25 and 20 Hz. The IT returned a single value of resistance (Rinit) calculated by dividing the immediate change in tracheal pressure occurring upon interruption by the preinterruption flow. We found Rinit to coincide closely with Re(f) in the frequency range 5–20 Hz. Rinit has previously been interpreted as the high-frequency resistance of a resistance-elastance model of the respiratory system airways and tissues. It has also been shown previously, by direct measurement of alveolar pressure in dogs, that Rinit from the lungs alone is an accurate measure of airways resistance while Rinit obtained from the total respiratory system equals airways resistance plus a modest contribution from the chest wall. Re(f) at a frequency of approximately 10 Hz thus appears to be a useful quantity to measure as an index of airways resistance in the dog.

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.

Influence of human vocal cord movements on airflow and resistance during eupnea

1982 ◽  
Vol 52 (3) ◽  
pp. 773-779 ◽  
Author(s):  
S. J. England ◽  
D. Bartlett ◽  
J. A. Daubenspeck
Keyword(s):  
Vocal Cord ◽  
Respiratory System ◽  
Forced Oscillation Technique ◽  
Quiet Breathing ◽  
Vocal Cords ◽  
Healthy Human ◽  
Breathing Motion ◽  
Human Volunteers ◽  
Respiratory System Resistance ◽  
Respiratory Movements

The pattern of respiratory movements of the vocal cords in relation to airflow and respiratory system resistance was assessed in healthy human volunteers during quiet breathing. Motion pictures of the vocal cords were obtained through a fiber-optic laryngoscope inserted transnasally under topical anesthesia. A simultaneous estimate of lung volume was obtained using either rib cage and abdominal magnetometer coils or an integrated pneumotachograph signal. The vocal cords separated during inspiration and moved closer together during the expiratory phase of each breath. The extent of these movements varied greatly among the subjects. Total respiratory system resistance, assessed by the forced oscillation technique, was negatively correlated with distance between the vocal cords when measured at isoflow points in inspiration and expiration. Analysis of breath-by-breath variations in expiratory airflow and vocal cord position revealed that decreases in airflow accompanied decreases in the distance between the vocal cords. The results of this study indicate that the human larynx participates in the regulation of respiratory airflow by providing a variable, controlled resistance.

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.

Measurement of total respiratory impedance in calves by the forced oscillation technique

1988 ◽  
Vol 64 (5) ◽  
pp. 1786-1791 ◽  
Author(s):  
P. Gustin ◽  
A. R. Dhem ◽  
F. Lomba ◽  
P. Lekeux ◽  
K. P. Van de Woestijne ◽  
...  
Keyword(s):  
Resonant Frequency ◽  
Fourier Analysis ◽  
Respiratory System ◽  
Pressure Wave ◽  
Forced Oscillation ◽  
Forced Oscillation Technique ◽  
Respiratory Impedance ◽  
Upper Airways ◽  
Low Frequencies ◽  
Spontaneously Breathing

We have determined the resistance (Rrs) and the reactance (Xrs) of the total respiratory system in unsedated spontaneously breathing calves at various frequencies. A pseudorandom noise pressure wave was produced at the nostrils of the animals by means of a loudspeaker adapted to the nose by a tightly fitting mask. A Fourier analysis of the pressure in the nostrils and flow signals yielded mean Rrs and Xrs, over 16 s, at frequencies of 2–26 Hz. A good correlation was found between values of pulmonary resistances measured by the isovolume method at the respiratory frequency of animals and values obtained at a frequency of 6 Hz by use of our technique. The linearity of the respiratory system, the reproducibility of the technique, and the effects of upper airways on results have been studied. In healthy calves, Rrs increases with frequency. Mean resonant frequency is 7.5 Hz. Bronchospasm was induced in six calves by administration of intravenous organophosphates. Rrs tended to decrease with increasing frequency. Resonant frequency exceeded 26 Hz. All parameters returned to initial values after administration of atropine. In healthy calves, atropine produces a decrease in Rrs, especially at low frequencies. Values of resonant frequency are not modified.

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

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.

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