In:
Journal of Applied Physiology, American Physiological Society, Vol. 91, No. 6 ( 2001-12-01), p. 2767-2775
Abstract:
Respiratory inductance plethysmographic (RIP) and pneumotachographic (Pn) flows were compared dynamically in horses with bronchoconstriction. On a breath-by-breath basis, RIP was normalized to inspiratory volume from Pn, and peak [peak of subtracted final exhalation waveform (SFE max )] and selected area [integral of subtracted final waveform during first 25% of exhaled volume (SFE int )] differences between RIP and Pn flows during early expiration were measured in three settings: 1) healthy horses ( n = 8) undergoing histamine bronchoprovocation; 2) horses with naturally occurring lower airway obstruction (AO) ( n = 7); and 3) healthy horses ( n = 6) given lobeline · HCl to induce hyperpnea. In setting 1, histamine challenge induced a dose-dependent increase in SFE max and SFE int differences. A test index of airway reactivity (interpolated histamine dose that increased SFE max by 35%) closely correlated ( r s = 0.93, P = 0.001) with a conventional index (histamine dose that induced a 35% decrease in dynamic compliance). In setting 2, in horses with AO, SFE max and SFE int were markedly elevated, and their absolute values correlated significantly ( P 〈 0.005) with pulmonary resistance and the maximum change in transpulmonary pressure. The effects of bronchodilator treatment on the SFE max and SFE int were also highly significant ( P 〈 0.0001). In setting 3, hyperpnea, but not tachypnea, caused significant ( P 〈 0.01) increases in SFE max but not in SFE int . In conclusion, dynamic comparisons between RIP and Pn provide a defensible method for quantifying AO during tidal breathing, without the need for invasive instrumentation.
Type of Medium:
Online Resource
ISSN:
8750-7587
,
1522-1601
DOI:
10.1152/jappl.2001.91.6.2767
Language:
English
Publisher:
American Physiological Society
Publication Date:
2001
detail.hit.zdb_id:
1404365-8
SSG:
12
SSG:
31
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