<i>Physical Dynamics of the Cough Mechanism</i>

Roß, Bernhard; Gramiak, Raymond; Rahn, Hans-Juergen

doi:10.1152/jappl.1955.8.3.264

Cited by 142 publications

(65 citation statements)

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“…In normal lungs there is both a high flow rate and a significant decrease in the caliber of the airways. Both of these mechanisms serve to increase velocity, which has been estimated to approach the speed of sound (18), although this is probably an overestimate (7). In airway obstruction, however, the flow rates are grossly restricted.…”

Section: Discussionmentioning

confidence: 99%

Bronchial Pressure Measurements in Emphysema and Bronchitis*

Macklem¹,

Fraser²,

Brown³

1965

J. Clin. Invest.

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Koblet and Wyss were the first to use bronchial pressure measurements to locate the airway obstruction in emphysema and asthma (1). Their results showed that in emphysema expiratory obstruction occurred in large airways whereas in asthma it was in small airways. It had already been established, in particular by Dayman (2), that emphysema was characterized by a marked increase in airway resistance during forced expiration, due to airway compression, and that this increase limited expiratory flow. Subsequently Hyatt, Schilder, and Fry (3) and Fry and Hyatt (4) showed that the inability of the patient with emphysema to breathe was directly attributable to expiratory airway compression and that maximal expiratory flow bore a unique relationship to lung volume. Out of these investigations grew the concept of the "flow-limiting segment," which was regarded as the airway or airways which were the first to narrow enough to limit flow. Thus, Koblet and Wyss's work took on added importance because it suggested that the flow limitation in emphysema was due to narrowing of large bronchi. Our laboratory has confirmed and extended their results by measuring bronchial pressures during cinebronchography (5). It was found that in emphysema the expiratory obstruction as demonstrated by the pressure measurements coincided with collapse of the lobar bronchi visualized cinebronchographically. Furthermore, this collapse * Submitted for publication October 9, 1964; accepted February 11, 1965. This appeared to be the result of an increase in bronchial compliance.These investigations suggested that the collapsing lobar bronchi were flow limiting in emphysema. This was not proven, as the possibility remained that flow was initially limited in smaller airways and that subsequent to this event the lobar bronchi collapsed obstructing flow. The crucial role played by the small airways would thus be masked, and the lobar bronchi would spuriously appear as the flow-limiting segments. The present study was designed to investigate this problem further. MethodsSubjects. Nine patients were studied. The only criterion for inclusion in the study was chronic airway obstruction with a reduction in forced expiratory volume in the first three-quarters of a second (FEVo.75) that was unresponsive to therapy. Thus, all patients with episodic asthma were excluded. Included were six patients who, on the basis of clinical findings and lung function tests, were thought to have emphysema and three patients who were thought to have chronic airway obstruction due to bronchitis without emphysema. The criteria for making this distinction have been previously described (5, 6). The three function tests used in the differentiation are the diffusing capacity, maximal negative static transpulmonary pressure, and over-all lung compliance. For the present purposes it was arbitrarily decided that nor -TABLE I

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Section: Discussionmentioning

confidence: 99%

Bronchial Pressure Measurements in Emphysema and Bronchitis*

Macklem¹,

Fraser²,

Brown³

1965

J. Clin. Invest.

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“…Studies in normal subjects who were instructed to cough voluntarily suggest that the inspiratory volume relates to the anticipated forcefulness of the subsequent expulsive effort [12,13]. With a "gentle" cough effort, the mean volume of inspired air has been shown to be about 0.4 l, whereas with a maximum cough effort the mean inspired volume was 2.5 l. The mean time required for air intake varied to a much lesser extent, being 0.75 s and 0.65 s with a gentle and a maximum cough, respectively.…”

Section: The 3-phase Motor Pattern Of Voluntary and Reflex Coughsmentioning

confidence: 99%

Voluntary and reflex cough: Similarities and differences

Magni¹,

Chellini²,

Lavorini³

et al. 2011

Pulmonary Pharmacology & Therapeutics

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Cough is defensive airway reflex subjected to a high degree of cortical control. Not surprisingly, all cough motor patterns can be mimicked and reflex cough be inhibited up to complete suppression, at least to a certain extent. Reflex cough differentiates from other airway reflex responses for its characteristic 3-phase motor pattern, and such pattern is maintained when coughing is produced voluntarily. Despite these and some other similarities, voluntary and reflex cough differ in many important respects, suggesting different neural control of the respiratory and non-respiratory musculature implicated in the generation of the cough modalities. This paper focuses the motor features that differentiate voluntary and reflex cough efforts, and highlights the importance of functional assessment of coughing in the diagnostic workup of respiratory and extra-respiratory diseases affecting the production of voluntary and reflex cough.

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“…La valoración funcional respiratoria del paciente que presenta enfermedad neuromuscular es un parámetro fundamental en su manejo terapéutico, teniendo en cuenta que una de las complicaciones de más relevancia es la tos inefectiva y la incapacidad para movilizar secreciones (24,25). Uno de los parámetros de evaluación es la medida de flujo pico durante la tos (26,27), técnica que ha demostrado utilidad en la práctica clínica (28,29) y se correlaciona con las pruebas convencionales de función pulmonar y muscular, tanto en el paciente sano como en aquel con enfermedad neuromuscular (30).…”

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