| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Laboratory of Cardiorespiratory Physiology, Brussels School of Medicine, 1070 Brussels, Belgium2 Chest Service, Erasme University Hospital, 1070 Brussels, Belgium3 Intensive Care Unit, Saint-Pierre University Hospital, 1000 Brussels, Belgium
The coupling between the ribs and the lung in dogs increases with increasing rib number in the cranial part of the rib cage and then decreases markedly in the caudal part. The hypothesis was raised that this non-uniformity is primarily related to differences between the areas of the lung subtended by the different ribs, and in the current study we tested this idea by assessing the effects of passive lung inflation. Thus, by causing a descent of the diaphragm, inflation would expand the area of the lung subtended by the caudal ribs and improve the coupling between these ribs and the lung. The axial displacements of the ribs and the changes in airway opening pressure (
Pao) were measured in anaesthetized, pancuronium-treated, supine dogs while loads were applied in the cranial direction to individual rib pairs at functional residual capacity (FRC) and after passive inflation to 10 and 20 cmH2O transrespiratory pressure. In agreement with the hypothesis, inflation caused an increase in Pao for ribs 9 and 10. The most prominent alteration, however, was a marked decrease in Pao for ribs 2–8; at 20 cmH2O, Pao for these ribs was only 30% of the value at FRC. Additional measurements indicated that this decrease in Pao results partly from the increase in diaphragmatic compliance but mostly from the reduction in outward rib displacement. This alteration in the pattern of rib motion should add to the decrease in muscle length to reduce the lung expanding action of the external intercostal muscles at high lung volumes.
(Received 21 October 2003;
accepted after revision 15 December 2003;
first published online 23 December 2003)
Corresponding author A. De Troyer: Chest Service, Erasme University Hospital, Route de Lennik, 808, 1070 Brussels, Belgium. Email: a_detroyer{at}yahoo.fr
This article has been cited by other articles:
|
|
 |
|
  A. De Troyer and D. Leduc Effects of single-lung inflation on inspiratory muscle function in dogs J. Physiol., October 1, 2006; 576(1): 269 - 277. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. De Troyer and D. Leduc Effect of diaphragmatic contraction on the action of the canine parasternal intercostals J Appl Physiol, July 1, 2006; 101(1): 169 - 175. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Leduc and A. D. Troyer The effect of lung inflation on the inspiratory action of the canine parasternal intercostals J Appl Physiol, March 1, 2006; 100(3): 858 - 863. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. De Troyer, P. A. Kirkwood, and T. A. Wilson Respiratory Action of the Intercostal Muscles Physiol Rev, April 1, 2005; 85(2): 717 - 756. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
