| How does HeO2 increase maximum expiratory flow in human lungs? | |
| | |
MedLine Citation:
|
PMID: 7419718 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
We used the retrograde catheter technique to investigate the effect of HeO2 on resistance to maximum expiratory flow (Vmax) in airways subsegments between alveoli and the equal pressure point (EPP), and between EPP and the flow-limiting segment (FLS). FLS were found at the same airway site in sublobar bronchi (i.d., 0.54 +/- 0.13 cm) on both air and HeO2 in the six human excised lungs studied. Static elastic recoil pressure (5 +/- 1 cm H2O) and the lateral pressure at FLS (critical transmural airway pressure -6 +/- 3 cm H2O) were not different on the two gases. delta Vmax averaged 37 +/- 8.9% and was similar to the value found in healthy subjects of similar age (66 +/- 10 yr). EPP were located on HeO2 in peripheral airways (i.d., 0.33 +/- 0.03 cm), and EPP on air were located more downstream. Resistance between EPP and FLS was highly density dependent. Resistance between alveoli and EPP behaved as if it were density independent, due in part to Poiseuille flow in the peripheral airways and in part to the consequent narrowing of peripheral airways on HeO2. This density-independent behavior in peripheral airways reduced delta Vmax on HeO2 from its predicted maximal amount of 62%. Assuming that FLS is the "choke point" these findings are consistent with wave-speed theory of flow limitation modified to include functionally density-independent pressure losses in peripheral airways. These results and conclusions are similar to those found in living dogs. They question previous interpretation of delta Vmax as an index of peripheral airway obstruction, and demonstrate the utility of the wave-speed theory in explaining complicated mechanisms of expiratory flow limitation. |
| | |
Authors:
|
S N Mink; L D Wood |
Related Documents
:
|
11345158 - Comparative oral and topical decongestant effects of phenylpropanolamine and d-pseudoep... 3298198 - Effects of continuous positive airway pressure on upper airway and respiratory muscle a... 10598608 - Pharyngeal mucosal pressure and perfusion: a fiberoptic evaluation of the posterior pha... 17946318 - Airflow velocities in the airways during expiration on different end-expiratory lung vo... 3724988 - Normal cerebrospinal fluid pressure in the newborn. 7311168 - Effects of nicardipine on the cross-perfused canine atrium. |
Publication Detail:
|
Type: In Vitro; Journal Article |
Journal Detail:
|
Title: The Journal of clinical investigation Volume: 66 ISSN: 0021-9738 ISO Abbreviation: J. Clin. Invest. Publication Date: 1980 Oct |
Date Detail:
|
Created Date: 1980-12-16 Completed Date: 1980-12-16 Revised Date: 2010-09-10 |
Medline Journal Info:
|
Nlm Unique ID: 7802877 Medline TA: J Clin Invest Country: UNITED STATES |
Other Details:
|
Languages: eng Pagination: 720-9 Citation Subset: AIM; IM |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Aged Airway Resistance / drug effects Forced Expiratory Flow Rates* Helium / pharmacology* Humans Male Maximal Expiratory Flow Rate* Middle Aged Oxygen / pharmacology* Pulmonary Ventilation / drug effects Respiration* |
| Chemical | |
Reg. No./Substance:
|
7440-59-7/Helium; 7782-44-7/Oxygen |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Effect of high and low density lipoproteins on proliferation of cultured bovine vascular endothelial...
Next Document: Demonstration of a lack of change in serum 1 alpha,25-dihydroxyvitamin D in response to parathyroid ...