HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Free Full Text (PDF) Free All Versions of this Article: 100/3/858    most recent 00739.2005v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Leduc, D. Articles by Troyer, A. D. Search for Related Content PubMed PubMed Citation Articles by Leduc, D. Articles by Troyer, A. D.

The effect of lung inflation on the inspiratory action of the canine parasternal intercostals

¹Laboratory of Cardiorespiratory Physiology, Brussels School of Medicine; ²Intensive Care Unit, Saint-Pierre University Hospital; and ³Chest Service, Erasme University Hospital, Brussels, Belgium

Submitted 22 June 2005 ; accepted in final form 16 November 2005

Inflation induces a marked decrease in the lung-expanding ability of the diaphragm, but its effect on the parasternal intercostal muscles is uncertain. To assess this effect, the phrenic nerves and the external intercostals were severed in anesthetized, vagotomized dogs, such that the parasternal intercostals were the only muscles active during inspiration, and the endotracheal tube was occluded at different lung volumes. Although the inspiratory electromyographic activity recorded from the muscles was constant, the change in airway opening pressure decreased with inflation from –7.2 ± 0.6 cmH₂O at functional residual capacity to –2.2 ± 0.2 cmH₂O at 20-cmH₂O transrespiratory pressure (P < 0.001). The inspiratory cranial displacement of the ribs remained virtually unchanged, and the inspiratory caudal displacement of the sternum decreased moderately. However, the inspiratory outward rib displacement decreased markedly and continuously; at 20 cmH₂O, this displacement was only 23 ± 2% of the value at functional residual capacity. Calculations based on this alteration yielded substantial decreases in the change in airway opening pressure. It is concluded that, in the dog, 1) inflation affects adversely the lung-expanding actions of both the parasternal intercostals and the diaphragm; and 2) the adverse effect of inflation on the parasternal intercostals is primarily related to the alteration in the kinematics of the ribs. As a corollary, it is likely that hyperinflation also has a negative impact on the parasternal intercostals in patients with chronic obstructive pulmonary disease.

respiratory muscle mechanics; rib motion; diaphragm compliance

This article has been cited by other articles:

				D. Leduc and A. De Troyer Mechanism of increased inspiratory rib elevation in ascites J Appl Physiol, September 1, 2009; 107(3): 734 - 740. [Abstract] [Full Text] [PDF]

				D. K. McKenzie, J. E. Butler, and S. C. Gandevia Respiratory muscle function and activation in chronic obstructive pulmonary disease J Appl Physiol, August 1, 2009; 107(2): 621 - 629. [Abstract] [Full Text] [PDF]

				A. De Troyer and T. A. Wilson Effect of acute inflation on the mechanics of the inspiratory muscles J Appl Physiol, July 1, 2009; 107(1): 315 - 323. [Abstract] [Full Text] [PDF]

				S. Parthasarathy, A. Jubran, F. Laghi, and M. J. Tobin Sternomastoid, rib cage, and expiratory muscle activity during weaning failure J Appl Physiol, July 1, 2007; 103(1): 140 - 147. [Abstract] [Full Text] [PDF]

				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]