Respiratory muscle activities after birth in asphyxiated preterm lambs

A. A. Hutchison, J. A. Wozniak, H. G. Choi, R. A. Otto, R. M. Abrams, P. C. Kosch

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Laryngeal and pump muscle activities are important in the establishment and maintenance of functional residual capacity (FRC) after birth. The aim of this study was to determine the expiratory mechanisms by which laryngeal and diaphragmatic activities achieve the increments in FRC postnatally. Wire electrodes were placed in: the laryngeal abductor, a major laryngeal adductor, the inferior pharyngeal constrictor and the diaphragm of six fetal sheep. The lambs were delivered prematurely by cesarean section and a face mask with a pneumotachograph applied. A grunting respiratory pattern was characterized by severe expiratory airflow retardation, associated with laryngeal adductor activity. In grunting breaths, minimal volume loss at end-expiration and incremental increases in FRC occurred when the onset of diaphragmatic activity preceded the onset of laryngeal muscle activities associated with laryngeal opening. Thus the timing order of laryngeal and diaphragmatic muscle activities near end-expiration is a determinant of increments in FRC.

Original languageEnglish (US)
Pages (from-to)241-248
Number of pages8
JournalActa Paediatrica, International Journal of Paediatrics
Issue number3
StatePublished - 1994
Externally publishedYes


  • diaphragm
  • functional residual capacity
  • laryngeal muscles

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health


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