Airway Resistance Measurements in the Internist's Office Routine determination in the diagnosis and care of breathless patients

Cohen, Bevin; McIlreath, Fred J.

doi:10.3109/02770906809100261

Cited by 12 publications

(2 citation statements)

References 22 publications

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“…Nasal (Rn) and lower (Ra) air way resistances and the volume of thoracic gas (Vtf.) were measured with a wholebody, volume-displacement plethysmograph [13,14]; the sum of R" and Ra ([R" + Ra]) constituted total airway resistance, and the product of Ra and VtK was our index of specific airway resistance (sRa) [15]. Forced expiratory volume (FVC), that portion exhaled during the first second (FEV,.0), and maximal mid-expiratory flow rate (MMEFR) were calculated from the flow, volume and pressure traces in scribed with a direct-writing, high frequency oscillograph4 wedded to the plethys mograph output [16]; the same system recorded cough dynamics.…”

Section: Methodsmentioning

confidence: 99%

Respiratory and Cough Mechanics in Antitussive Trials

Cohen¹

1975

Respiration

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The relative responsitivy of nine expirographic and airway indices to antitussive therapy was studied in a randomized double-blind trial in which 60 adults without bronchopulmonary disorders, but suffering from common colds, were given oral doses of five drug formulations placebo during their initial 48 h of symptoms. Thoracic gas volume (V_tg), nasal (R_n), lower (R_a), total ([R_n + R_a]) and specific (sR_a) airway resistances were determined plethysmographically; forced vital capacity (FVC), forced expiratory volume for the first second (FEV_1.0) and maximal mid-expiratory flow rate (MMEFR) were recorded spirometrically. Cough pressure at peak flow furnished an index of cough (CI). The measurements were made at baseline and for 4 h after drug; medication was continued for two additional doses and the indices determined again the following morning. Abnormal control means were noted for R_n and [R_n + R_a] (90.8%), cough resistance (83.3%), MMEFR (58.3%), R_a and sR_a (30.0%), but less often for FEV_1.0, V_tg and FVC (6.6, 5.1 and 0.0%, respectively). Nasal and total airways flow resistance means were as sensitive to active therapy and in discriminating the relative worth of medication as direct CI values, R_a and sR_a were less reliable, and the three spirometric functions were the least responsive. This ranking was consistent with the common central airways location of subepithelial receptors responsible for cough and the associated reflex bronchoconstriction. The greatest changes in cough resistance followed treatment with the most significant activity in the nasal, as well as the lower tract, component of total airway resistance.

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Section: Methodsmentioning

confidence: 99%

Respiratory and Cough Mechanics in Antitussive Trials

Cohen¹

1975

Respiration

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“…Airway resistance (Ra) and the related volume of thoracic gas (Vtg) were measured with subjects seat ed in a whole-body volume-displacement plethysmograph modified (MacDerjhs Co., Sepulveda, Calif.) [2] from Mead's adaptation [3] of the design of DuBois et at. [4].…”

Section: Methodsmentioning

confidence: 99%

Color Presentation of Breath Sounds

Cohen¹

1972

Respiration

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A simple ‘color-organ’-loudspeader assembly was connected to a microphone inserted in the mouthpiece of a whole body volume-displacement plethysmograph to record panting breath sound frequencies as color patterns for 50 normal subjects studied at rest, and 150 patients with chronic obstructive ventilatory disorders examined before, and 5 min after inhalation of an isoproterenol-phenylephrine aerosol. The color displays were related to spirometric and plethysmographic indices. The respiratory function means were poorest for subjects breathing in the blue (lowest) frequency range, with increasingly better mean data for groups in the mixed blue/red, red and green frequencies. Although there was a modest degree of overlapping between the groups, differences in intergroup means were significant at the 0.01 level or better for all indices except certain Vtg comparisons. The breath sounds of the majority of normal subjects fell into the green or red (highest) frequencies, with the progressively abnormal function of the patient subdivisions marked by increasing numbers breathing in the blue/red and blue ranges. These color patterns were function-directed, rather than primarily related to age or diagnosis. Improved mean indices following bronchodilator mist exposure were accompanied by a shift into higher color frequencies, with changes in [Rg×Vtg] and Ra of equal magnitude to alterations in FEF_{200 – 1,200} and FEV_1•0These data suggest that color presentation of oral respiratory sounds is a simple and inexpensive semi-quantitative method of estimating ventilatory status and the response to bronchoactive drugs.

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Nasal surgery and airway resistance

Kosoy¹

1979

The Laryngoscope

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This study investigates the effects of surgery and bronchodilatation on nasal and pulmonary resistance. The plethysmograph is evaluated as a clinical tool for nasal flow studies. The method of adapting the plethysmograph to measure nasal resistance is presented. Discriminant Function Analysis considers the effects of surgery and bronchodilatation on 15 variables. The statistical analysis of 38 cases demonstrates the benefits of improved nasal airway for pulmonary airway resistance. A review of the literature points out many of the difficulties in measuring nasal airflow. The plethysmograph emerges as an available easily adapted clinical tool that overcomes many of the short‐comings in earlier techniques and in rhinomanometry. The rhinologist is offered further insight into the nasopulmonary relationship and the use of the plethysmograph to document the effects of nasal surgery.

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Airway Resistance Measurements in the Internist's Office Routine determination in the diagnosis and care of breathless patients

Cited by 12 publications

References 22 publications

Respiratory and Cough Mechanics in Antitussive Trials

Respiratory and Cough Mechanics in Antitussive Trials

Color Presentation of Breath Sounds

Nasal surgery and airway resistance

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