Low Crs Research Articles

DECLINE IN RESPIRATORY COMPLIANCE DURING THE FIRST WEEK OF LIFE IN INFANTS ≤ 1000 g

Single measurements of respiratory compliance (Crs) in premature infants have been reported; however serial recordings have not been published. Monitoring respiratory mechanics could improve ventilation techniques. Using a non-invasive single breath occlusion technique (LeSouef et al: Am Rev Resp Dis 129:521, 1984) Crs was measured serially in 10 ventilated infants ≤ 1000 g. 2 infants with very low Crs ≤ .25 ml·cm H2O−1 died on day 1 from respiratory failure. In a further 2 infants with severe lung disease (Mean airway pressure [MAP] 12-15 cm H2O on day 2) no change in Crs occurred throughout the first week (.4-.5 ml· cmH2O−1). Six infants showed a striking decline in Crs (Table). This fall in Crs was also seen in those infants ventilated mainly for apneas: MAP in cases 1-3 ranged from 3.5-7.2 cm H2O during the first week, and FiO2 from .21-.34. We conclude that even modest mechanical ventilation in infants ≤ 1000 g may be associated with an early, rapid and progressive decline in. Crs.

1849 TOTAL RESPIRATORY SYSTEM COMPLIANCE IN INFANTS WITH CYSTIC FIBROSIS

In the only study to measure dynamic pulmonary compliance (C) in cystic fibrosis infants (CFI) it was low. Esophageal catheters were used, but these are invasive and may be inaccurate due to chest wall distortion. We evaluated weighted spirometry technique for measuring total respiratory system compliance (Crs) in CFI. We studied during sleep 5 CFI and 9 normal controls (NC) mean ages 6.1 and 6.2 months. We tested respiratory rate (RR), functional residual capacity (FRC) by helium dilution, mixing index (MI), specific total respiratory system compliance, Crs'=Crs/FRC, and size corrected flows (VmaxFRC/FRC) by rapid chest compression.CFI had lower Crs' than NC but similar flows. In the absence of small airways dysfunction, the low Crs' and higher RR in CFI could result from increased elastic recoil since Crs' should be quasi static after equilibration of pressure to all lung units. However, the low MI and high FRC in CFI indicates small airway dysfunction. Thus, the low Crs may be secondary to frequency dependence. We conclude that Crs is low in CFI and represents a non-invasive method for assessing early pulmonary dysfunction. Supported by NIH Grant #HL01322-01, HL990-03 and ALA Fellowship.

THE NERVOUS CONTROL OF RESPIRATION IN KITTENS

ArticleTHE NERVOUS CONTROL OF RESPIRATION IN KITTENSHelen C. Coombs, and F. H. PikeHelen C. CoombsFrom the Department of Physiology, New York Homeopathic Medical College, and Columbia University, and F. H. PikeFrom the Department of Physiology, New York Homeopathic Medical College, and Columbia UniversityPublished Online:01 Dec 1930https://doi.org/10.1152/ajplegacy.1930.95.3.681MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByPostnatal development of right atrial injection of capsaicin-induced apneic response in ratsRurong Wang, and Fadi Xu1 July 2006 | Journal of Applied Physiology, Vol. 101, No. 1Hypoxemia and low Crs in vagally denervated lambs result from reduced lung volume and not pulmonary edemaSalim Lalani, John E. Remmers, Yolanda MacKinnon, Gordon T. Ford, and Shabih U. Hasan1 August 2002 | Journal of Applied Physiology, Vol. 93, No. 2Effects of vagal denervation on cardiorespiratory and behavioral responses in the newborn lambSalim Lalani, John E. Remmers, Francis H. Green, Ashfaq Bukhari, Gordon T. Ford, and Shabih U. Hasan1 November 2001 | Journal of Applied Physiology, Vol. 91, No. 5Pulmonary vagal innervation is required to establish adequate alveolar ventilation in the newborn lambKevin A. Wong, Ather Bano, Anita Rigaux, Bing Wang, Baikhunth Bharadwaj, Samuel Schürch, Francis Green, John E. Remmers, and Shabih U. Hasan1 September 1998 | Journal of Applied Physiology, Vol. 85, No. 3 More from this issue > Volume 95Issue 3December 1930Pages 681-693 Copyright & PermissionsCopyright © 1930 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1930.95.3.681History Received 20 September 1930 Published online 1 December 1930 Published in print 1 December 1930 Metrics