Variability of Plethysmographic Measurements of Airway Resistance During the Day in Normal Subjects and in Patients with Bronchial Asthma and Chronic Bronchitis

Respiration ◽  
1971 ◽  
Vol 28 (2) ◽  
pp. 158-166 ◽  
Author(s):  
S. Zedda ◽  
E. Sartorelli
Keyword(s):  
Chronic Bronchitis ◽  
Bronchial Asthma ◽  
Airway Resistance ◽  
Normal Subjects

Site of airway obstruction in pulmonary disease: direct measurement of intrabronchial pressure

1992 ◽  
Vol 72 (3) ◽  
pp. 1016-1023 ◽  
Author(s):  
M. Yanai ◽  
K. Sekizawa ◽  
T. Ohrui ◽  
H. Sasaki ◽  
T. Takishima
Keyword(s):  
Chronic Bronchitis ◽  
Bronchial Asthma ◽  
Airway Resistance ◽  
Lateral Pressure ◽  
Airflow Obstruction ◽  
Lower Lobe ◽  
Transpulmonary Pressure ◽  
Normal Subjects ◽  
Peripheral Airway ◽  
The Right

To partition the central and peripheral airway resistance in awake humans, a catheter-tipped micromanometer sensing lateral pressure of the airway was wedged into the right lower lobe of a 3-mm-ID bronchus in 5 normal subjects, 7 patients with chronic bronchitis, 8 patients with emphysema, and 20 patients with bronchial asthma. We simultaneously measured mouth flow, transpulmonary pressure, and intra-airway lateral pressure during quiet tidal breathing. Total pulmonary resistance (RL) was calculated from transpulmonary pressure and mouth flow and central airway resistance (Rc) from intra-airway lateral pressure and mouth flow. Peripheral airway resistance (Rp) was obtained by the subtraction of Rc from RL. The technique permitted identification of the site of airway resistance changes. In normal subjects, RL was 3.2 +/- 0.2 (SE) cmH2O.l-1.s and the ratio of Rp to RL was 0.24 during inspiration. Patients with bronchial asthma without airflow obstruction showed values of Rc and Rp similar to those of normal subjects. Although Rc showed a tendency to increase, only Rp significantly increased in those patients with bronchial asthma with airflow obstruction and patients with chronic bronchitis and emphysema. The ratio of Rp to RL significantly increased in three groups of patients with airflow obstruction (P less than 0.01). These observations suggest that peripheral airways are the predominant site of airflow obstruction, irrespective of the different pathogenesis of chronic airflow obstruction.

Calculation of the VD/VT ratio by the helium washout technique

1986 ◽  
Vol 70 (6) ◽  
pp. 565-569 ◽  
Author(s):  
J. Jordanoglou ◽  
G. Tatsis ◽  
Z. Bissiouli
Keyword(s):  
Pulmonary Fibrosis ◽  
Chronic Bronchitis ◽  
Bronchial Asthma ◽  
Conventional Method ◽  
Normal Subjects

1. In four normal subjects and 51 patients with chronic bronchitis-emphysema, bronchial asthma and pulmonary fibrosis, the VD/VT ratio was measured by a helium washout technique (w VD/VT) and by the conventional Bohr's method using the arterial CO2 tension (VD/VT). 2. In 16 patients the w VD/VT ratio was compared with that calculated from Bohr's equation with the alveolar CO2 tension measured by the rebreathing technique (A VD/VT). 3. It was found that the values for the VD/VT ratio obtained by the helium washout technique were very close to those obtained by the conventional method using the Paco2 or P¯Aco2 values.

scholarly journals Measurement of Airway Resistance in Bronchial Asthma and in Emphysema-Chronic Bronchitis

1982 ◽  
Vol 29 (4) ◽  
pp. 196-204
Author(s):  
Sung Koo Han ◽  
Myung Hae Lee ◽  
Young Hyun Lee ◽  
Young Soo Shim ◽  
Keun Youl Kim ◽  
...  
Keyword(s):  
Chronic Bronchitis ◽  
Bronchial Asthma ◽  
Airway Resistance

Frequency response of the chest: modeling and parameter estimation

1975 ◽  
Vol 39 (4) ◽  
pp. 523-534 ◽  
Author(s):  
R. Peslin ◽  
J. Papon ◽  
C. Duviver ◽  
J. Richalet
Keyword(s):  
Frequency Response ◽  
Gas Flow ◽  
Airway Resistance ◽  
Mechanistic Model ◽  
Normal Subjects ◽  
Order Equation ◽  
Mean Values ◽  
Tissue Compliance ◽  
Linear Differential ◽  
Gas Compressibility

The frequency response of the respiratory system was studied in the range from 3 to 70 Hz in 15 normal subjects by applying sinusoidal pressure variations around the chest and measuring gas flow at the mouth. The observed input-output relationships were systematically compared to those predicted on the basis of linear differential equations of increasing order. From 3 to 20 Hz the behavior of the system was best described by a 3rd-order equation, and from 3 to 50 Hz by a 4th-order one. A mechanistic model of the 4th order, featuring tissue compliance (Ct), resistance (Rt) and inertance (It), alveolar gas compressibility (Cg) and airway resistance (Raw), and inertance (Iaw) was developed. Using that model, the following mean values were found: Ct = 2.08–10(-2)1-hPa-1 (1 hPa congruent to 1 cm of water); Rt = 1.10-hPa-1(-1)-s; It = 0.21–10(-2)hPa-1(-1)-s2; Raw = 1.35-hPa-1(-1)-s; Iaw = 2.55–10(-2)hPa-1(-1)-s2. Additional experiments devised to validate the model were reasonably successful, suggesting that the physical meaning attributed to the coefficients was correct. The validity of the assumptions and the physiological meaning of the coefficients are discussed.

Bronchoconstriction in man following single deep inspirations

1963 ◽  
Vol 18 (1) ◽  
pp. 114-116 ◽  
Author(s):  
Thomas C. Lloyd
Keyword(s):  
Airway Resistance ◽  
Normal Subjects ◽  
Closed Glottis

Consistent small transient increases in airway resistance were observed to occur following maximal inspirations by a number of normal subjects. The same effect was also seen after merely attempting inspiration against a closed glottis, and both this and the response after deep inhalation were blocked by prior inhalation of a bronchodilator. An active bronchomotor mechanism is postulated for this response. Submitted on January 24, 1962

Airway resistance measurement during any breathing pattern in man

1959 ◽  
Vol 14 (1) ◽  
pp. 89-96 ◽  
Author(s):  
R. G. Bartlett ◽  
H. F. Brubach ◽  
R. C. Trimble ◽  
H. Specht
Keyword(s):  
Body Temperature ◽  
Airway Resistance ◽  
Breathing Pattern ◽  
Continuous Measurement ◽  
Normal Subjects ◽  
Pulmonary Diseases ◽  
Alveolar Pressure ◽  
Improved Method ◽  
Compression And Expansion ◽  
Pressure Changes

A broadly applicable method for the quantitative and continuous measurement of airway resistance in man is described. It permits the simultaneous measurement of air flow (breath velocity) and alveolar pressure during any breathing pattern. Alveolar pressure is calculated from body plethysmograph pressure (plethysmogram) changes coincident with the compression and expansion of lung air during expiration and inspiration, respectively. The plethysmograph interior is maintained at body temperature and complete H2O saturation. This avoids the errors in measurement due to plethysmograph pressure changes produced by temperature and humidity changes in the inspired and expired breath and also obviates the necessity of using only a panting type breathing pattern. Data on three normal subjects at near resting and near maximum breathing efforts are presented and discussed. This improved method, permitting airway resistance measurements during any breathing pattern, should find application in diagnosis and assessment of treatment of pulmonary diseases as well as in the investigation of several basic pulmonary function problems. Submitted on June 17, 1958

Reversibility of Airways Obstruction in Chronic Bronchitis

1972 ◽  
Vol 42 (6) ◽  
pp. 725-733 ◽  
Author(s):  
T. W. Astin
Keyword(s):  
Muscle Contraction ◽  
Chronic Bronchitis ◽  
Lung Volume ◽  
Normal Subjects ◽  
Atropine Sulphate ◽  
Airways Obstruction ◽  
Chest Disease ◽  
Before And After ◽  
Airways Resistance ◽  
Intravenous Atropine

1. Airways resistance and lung volume were measured in twenty-five patients with chronic bronchitis and fifteen patients without chest disease before and after the inhalation of isoprenaline. Similar measurements were made on fourteen of these patients with chronic bronchitis and twelve other patients without chest disease before and after the intravenous injection of atropine sulphate. 2. There were significant decreases in airways resistance after isoprenaline inhalation and intravenous atropine both in patients with bronchitis and normal subjects but the decreases were greater in the patients with chronic bronchitis. 3. The decrease in resistance was proportional to the degree of initial airways resistance. 4. The results are considered to indicate that bronchial muscle contraction increases the airways resistance of patients with chronic bronchitis and contributes to the airways obstruction; its contribution increases with increasing severity of the condition. A significant part of the increased airways resistance in these patients is potentially reversible and nervously mediated.

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