1671a respiratory failure and the expiratory control of breathing in lambs


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ABSTRACT During quiet sleep (QS) in lambs phasic laryngeal adduction (Thyroarytenoid TA) is sufficient to elevate subglottic pressure to 10 cms H2O. This does not occur in active sleep


(AS).Present studies using chronically implanted emg electrodes, air flow and pressure measurements were to determine the contribution of the upper airway (larynx), and the diaphragm on the


maintenance of lung volume and respiratory drive. In QS respiratory frequency (RF) fell from 8 days to 32 days postnatal age [91±11 to 31±3 breaths min] and was related to an increase in


expiratory time (TE). Subglottic pressure, expiratory laryngeal resistance and integrated TA emg activity correlated well with TE.The diaphragm did not contract uniformly; up to 45% of the


contraction time of the vertebral diaphragm was expiratory whereas the paratendinous diaphragm contraction ceased at end-inspiration. Removing the positive airway pressure during expiration


by opening a tracheotomy caused 1) an increase in expiratory laryngeal adduction and in expiratory activity of the diaphragm; 2) a fall in respiratory frequency. Since vagal blockade had the


same effect, pulmonary vagal pressure-sensitive afferents control the laryngeal adductors and the expiratory activity of the diaphragm. Preventing expiratory resistance to airflow during QS


leads, to a loss of RF, lung volume and sometimes respiratory failure, overriding the normal chemical drive to breathing. This finding may relate to future sleep-related respiratory


failure. FSSID NO. 26. ARTICLE PDF AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * Nuffield Inst. Med. Res., University of Oxford, U.K. P Johnson, R Harding, D J Henderson-Smart & P


Ballard Authors * P Johnson View author publications You can also search for this author inPubMed Google Scholar * R Harding View author publications You can also search for this author


inPubMed Google Scholar * D J Henderson-Smart View author publications You can also search for this author inPubMed Google Scholar * P Ballard View author publications You can also search


for this author inPubMed Google Scholar RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Johnson, P., Harding, R., Henderson-Smart, D. _et al._ 1671A


RESPIRATORY FAILURE AND THE EXPIRATORY CONTROL OF BREATHING IN LAMBS. _Pediatr Res_ 15 (Suppl 4), 722 (1981). https://doi.org/10.1203/00006450-198104001-01690 Download citation * Issue Date:


01 April 1981 * DOI: https://doi.org/10.1203/00006450-198104001-01690 SHARE THIS ARTICLE Anyone you share the following link with will be able to read this content: Get shareable link


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