The Effect of Body Position Change on Lung Compliance in Normal Subjects and in Patients With Congestive Heart Failure*

Abstract

Since the work of Christie and Meakins (1), the lungs of patients with heart failure have been acknowledged to resist inflation to a greater extent than normal lungs. More recent studies of pulmonary mechanics in patients with congestive heart failure (2-5) have emphasized the lowered lung compliance as well as moderate increases in pulmonary resistance. That acute changes in lung compliance can occur in man has been shown by Saxton, Rabinowitz, Dexter and Haynes (6) who demonstrated acute decreases in lung compliance on exercise in patients with heart disease associated with increases in pulmonary artery wedge pressure, and by Bondurant, Hickam and Isley (7) who demonstrated acutely decreased compliance in normal subjects when transient pulmonary congestion was induced by sudden inflation of a pressurized suit. Because of the importance of body position in cardiac dyspnea, a feature of which is orthopnea, the present study was undertaken to determine what, if any, changes in the static volume-pressure characteristics of the lungs occurred in normal subjects and in orthopneic patients with heart failure on changing from the sitting to the horizontal (prone) body position. METHODSThe data herein presented were derived from simultaneous oscillographic recordings 1 of transpulmonary pressure, air flow and the tidal volume. Esophageal pressure was recorded by means of a balloon catheter (balloon length, 15 cm.) similar to that described by Mead, * Supported by grants from the American Heart Association. McIlroy, Selverstone and Kriete (8). It was inflated with 1 ml. of air when in use. This catheter was attached to one side of a differential pressure transducer 2 of low volume displacement with small and equal air volumes on the two sides of the diaphragm. The other side of the transducer was connected to the mouthpiece so that the pressure recorded represents the difference between pressures in the mouth and the esophagus or the transpulmonary pressure. The 95 per cent response time of this system was approximately 0.005 second and its natural frequency, 100 cycles per second. Airflow was recorded by measuring the differential pressure across a 400-mesh monel metal screen two inches in diameter by means of a differential pressure transducer 3 also provided with small and equal volumes on either side of the diaphragm. The 95 per cent response time of the flow recording system was 0.015 second and its natural frequency, 40 cycles per second. Tidal volume was recorded in early experiments on a 7 L. spirometer.4 To the spirometer counterweight was attached an electrical contact to a resistance wire which formed two arms of a resistance bridge activated by a mercury cell; the output of this bridge was fed into a DC amplifier. The output of this volume transducer was linearly related to volume. In later experiments a low resistance, low inertia Krogh spirometer 5 was used, at the fulcrum of which was attached an angular displacement transducer,8 the output of which was also linearly related to volume. Airflow was interru...

Broad individual immersion-scattering of respiratory compliance likely substantiates dissimilar breathing mechanics

“…Firstly, immersion increases the lung blood volume, causing a substantial decrease in parenchymal compliance 14 , 15 , 34 , 38 . In patients with congestive heart failure, a rapid 22% decrease in lung compliance was observed when they changed their position from sitting upright to lying down 39 . Secondly, lung compliance also decreases simply when the gaseous lung volume is reduced.…”

The Total Work of Breathing in Normal and Obese Men*

“…Static volume-pressure curves for the lung Pulmonary compliance and resistance and the work were measured by using an interrupter as previously done on the lung were calculated by conventional meth-described (21). Thoracic subtracting pulmonary resistance from the total respiratory system resistance.…”

Physiologic Changes Associated with Increasing Pulmonary Wedge Pressures in the Dog

“…1, 2). One possible explanation for the position-dependent changes of Pa0 2 is an increased return of blood into the thoracic cavity in the supine position and consequent decrease of pulmonary compliance [38]. This situa tion would potentiate an already borderline compromised V/Q relationship produced by an elevated PWP.…”