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Inspiratory resistive load detection in children with life‐threatening asthma
Author(s) -
Davenport Paul W.,
Kifle Yemiserach
Publication year - 2001
Publication title -
pediatric pulmonology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.866
H-Index - 106
eISSN - 1099-0496
pISSN - 8755-6863
DOI - 10.1002/ppul.1087
Subject(s) - bronchoconstriction , medicine , asthma , airway resistance , resistive touchscreen , cardiology , electrical engineering , engineering
Abstract The detection of inspiratory resistive (R) loads was studied in nonasthmatic children (NA), asthmatic children (A), and children with a history of life‐threatening asthma (LTA). It was hypothesized that the LTA children would have a reduced ability to detect added mechanical loads as measured by the Weber fraction, which assesses the resistive load detection threshold (ΔR 50 /R 0 ). Subjects were separated from the investigator, were seated in a soundproofed room, and breathed through a nonrebreathing valve with the inspiratory port connected to the loading manifold. The subject's inspiratory baseline resistance (R aw ) was measured by the interrupter method. Ten magnitudes of R loads and no‐load were presented randomly 10 times each for a single inspiration. The loads were presented in three trials. Subjects pressed a button if they detected the presence of a load. The ΔR 50 was determined from the % detection‐ΔR curve. R 0 was the sum of the subject's R aw and the minimal resistance of the apparatus. The ΔR 50 /R 0 for children with life‐ threatening asthma was significantly greater than for asthmatic and nonasthmatic children. The increased ΔR 50 /R 0 suggests that children with LTA are at risk of life‐threatening asthma attacks, in part because it requires a greater change in resistance above their baseline resistance before they sense an increased mechanical load such as presented to them by bronchoconstriction during an asthmatic attack. Pediatr Pulmonol. 2001; 32:44–48. © 2001 Wiley‐Liss, Inc.