Studies of Respiratory Air Flow in Measurement of Ventilatory Function DONALD F. PROCTOR, M.D.  Diseases of the Chest  Volume 22, Issue 4, Pages 432-444 (October 1952) DOI: 10.1378/chest.22.4.432 Copyright © 1952 The American College of Chest Physicians Terms and Conditions

FIGURE 1 Child, with nose clip in place, holding the pneumotachometer attached to standard rubber mouthpiece. Tubing runs from pneumotachometer to differential strain gage manometer. On right side of table is power supply unit and amplifier, and to the left of table is galvanometer oscillograph with camera. Diseases of the Chest 1952 22, 432-444DOI: (10.1378/chest.22.4.432) Copyright © 1952 The American College of Chest Physicians Terms and Conditions

FIGURE 2 C is a pneumotachogram similar to that found in 50 per cent of the normal subjects studied.—A and B are types found equally often in remaining 50 per cent of normals. Inspiration is above the line in each instance. Heavy vertical lines mark 0.1 seconds. Diseases of the Chest 1952 22, 432-444DOI: (10.1378/chest.22.4.432) Copyright © 1952 The American College of Chest Physicians Terms and Conditions

FIGURE 3 Diagramatic illustration of the forces involved in pulmonary ventilation. The viscosity forces and the resistance of the respiratory tract to the passage of gases oppose ventilatory movement in either direction. Lung elasticity always opposes inspiratory movement and assists expiratory movement. The intercostals and diaphragm assist inspiration and offer little or no resistance to expiratory movements. Chest elasticity during quiet breathing assists inspiration and opposes expiration but when the lungs have been inflated to a volume greater than 70 per cent of vital capacity chest elasticity opposes further inflation and assists expiration down to this volume. There is insufficient information as to the relative srtength of these forces but it is known that at the resting point in quiet breathing the force of chest elasticity equally opposes the force of lung elasticity. Diseases of the Chest 1952 22, 432-444DOI: (10.1378/chest.22.4.432) Copyright © 1952 The American College of Chest Physicians Terms and Conditions

FIGURE 4 (A) Inspiration above zero line, demonstrating increasingly large inspiratory volumes and correspondingly higher initial expiratory velocities. (B) 1. Normal tracing and 2. Inspiration still above line but accomplished by relaxing after forced expiration. Diseases of the Chest 1952 22, 432-444DOI: (10.1378/chest.22.4.432) Copyright © 1952 The American College of Chest Physicians Terms and Conditions

FIGURE 5 Illustrating the change in pattern when increasing resistance is added. Diseases of the Chest 1952 22, 432-444DOI: (10.1378/chest.22.4.432) Copyright © 1952 The American College of Chest Physicians Terms and Conditions

FIGURE 6 (A) Record from a normal dog. Upper tracing (IABP): intraperitoneal pressure; middle tracing: Pneumotachogram; lower tracing: intrapleural pressure. Zero straight lines represent atmospheric pressure and zero flow velocity. The time lines measure 0.1 seconds. Intrapeoneal pressure becomes negative at the onset of inspiration, then positive, and negative again at the onset of expiration. Intrapleural pressure becomes increasingly more negative as inspiration continues, returning to the base-line shortly after the onset of expiration. Large fluctuations in the intrapleural pressure coincide with the heart beat.—(B) Record from the same dog after the phrenic nerves have been severed. Peak flow in the pneumotachogram appears at the onset of inspiration, in contrast to the slow acceleration in figure 1A; velocity during the latter half of inspiration is relatively low. A curve of the intraperitoneal pressure exactly follows that of intrapleural pressure differing only in the degree of pressure change. Diseases of the Chest 1952 22, 432-444DOI: (10.1378/chest.22.4.432) Copyright © 1952 The American College of Chest Physicians Terms and Conditions

FIGURE 8 From left to right, pattern of a rapid vital capacity (A), pattern during voluntary maximum breathing capacity test using a tidal volume about 50 per cent of vital capacity (B), and pattern of maximum effort resulting from exercise (C). Studies made on a healthy young adult. Diseases of the Chest 1952 22, 432-444DOI: (10.1378/chest.22.4.432) Copyright © 1952 The American College of Chest Physicians Terms and Conditions

FIGURE 7 (A) This figure shows three inspiratory curves reduced to the same time base (that is, corrected for the difference in respiratory rates in the three animals from which the curves were taken). The curve after phrenicectomy shows peak inspiratory flow earlier in the cycle than in the normal dog. The curve in the spinal dog shows peak flow late in the inspiratory cycle.—(B) The two dotted lines in this figure show two theoretical curves of flow velocity which, when summated, combine to produce the curve shown with a solid line. One curve with peak flow early in inspiration, has the general characteristics of intercostal activity alone, as shown in the phrenicectomized animals. The other with a peak flow in inspiration resembles the inspiratory paterns obtained in spinal animals, where the diaphragms alone expand the lungs. The solid line is taken from an inspiratory pneumotachogram in a normal human. Diseases of the Chest 1952 22, 432-444DOI: (10.1378/chest.22.4.432) Copyright © 1952 The American College of Chest Physicians Terms and Conditions

FIGURE 9 Expiratory puff and inspiratory gasp. The rate at which high velocity is reached, and the rate at which deceleration occurs with maximum effort, in a young healthy male. Diseases of the Chest 1952 22, 432-444DOI: (10.1378/chest.22.4.432) Copyright © 1952 The American College of Chest Physicians Terms and Conditions

FIGURE 10 L.W., a patient with pulmonary tuberculosis bilateral, cavitation and pneumothorax. Dotted line shows maximum effort. Diseases of the Chest 1952 22, 432-444DOI: (10.1378/chest.22.4.432) Copyright © 1952 The American College of Chest Physicians Terms and Conditions

FIGURE 11 A.S., a patient with severe bronchial asthma and bronchiectasis and marked dyspnoea at rest. Maximum effort at right. Diseases of the Chest 1952 22, 432-444DOI: (10.1378/chest.22.4.432) Copyright © 1952 The American College of Chest Physicians Terms and Conditions

FIGURE 12 (B) M.T., a middle aged woman with bronchiectasis in all five lobes. (C) E.K., an adolescent girl with bilateral bronchiectasis. (D) E.F., a young woman with multilobar bronchiectasis. Diseases of the Chest 1952 22, 432-444DOI: (10.1378/chest.22.4.432) Copyright © 1952 The American College of Chest Physicians Terms and Conditions

FIGURE 13 P.P., a man with pulmonary emphysema and chronic cor pulmonale. Diseases of the Chest 1952 22, 432-444DOI: (10.1378/chest.22.4.432) Copyright © 1952 The American College of Chest Physicians Terms and Conditions

FIGURE 14 C.B., a patient with pulmonary emphysema. Diseases of the Chest 1952 22, 432-444DOI: (10.1378/chest.22.4.432) Copyright © 1952 The American College of Chest Physicians Terms and Conditions

FIGURE 15 E.K., Inspiration above the line. Note sudden acceleration at onset of inspiration but poor maintenance of velocity during this phase. Diseases of the Chest 1952 22, 432-444DOI: (10.1378/chest.22.4.432) Copyright © 1952 The American College of Chest Physicians Terms and Conditions