Abstract
Our knowledge of airways reactivity to inflammatory agonists is derived predominantly from tests dominated by large airway responsiveness. To determine directly, the histamine responsiveness of the smallest airways, eight normal and 11 asymptomatic asthmatic subjects were studied utilizing a wedged bronchoscope technique. A fiberoptic bronchoscope was wedged in the anterior segment of the right upper lobe and a double-lumen catheter was advanced through the working channel to its tip. With a constant flow of gas (5% CO2 in air) through one lumen of the catheter, pressure at the tip of the bronchoscope was measured with the subject breath-holding at FRC. Peripheral airways resistance (Rp) was measured at baseline and after saline, histamine (10, 50, 100 mg/ml) and isoproterenol (2 mg/ml) challenge through the bronchoscope. Baseline Rp of asthmatics (0.041 ± 0.015 cm H2O/ml/min; mean ± SE) was significantly greater than normal subjects (0.011 ± 0.003 cm H2O/ml/min; p = 0.019). The log of the concentration of histamine that caused a 100% increase in peripheral airways response was greater in the normal subjects than in the asthmatic subjects (p = 0.0114) and correlated with whole lung responsiveness to histamine in asthmatics (r = 0.847, p <0.05). Isoproterenol reversed completely the increase in Rp in normal subjects but not asthmatic subjects. The results of this study demonstrate that the resistance of the smallest peripheral airways, when measured directly, increased when challenged locally with histamine in both normal subjects and asthmatic subjects. However, the peripheral airways responsiveness was significantly enhanced in asthmatic subjects relative to normal controls.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 447-452 |
| Number of pages | 6 |
| Journal | American Journal of Respiratory and Critical Care Medicine |
| Volume | 157 |
| Issue number | 2 |
| State | Published - 1998 |
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ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine
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Direct assessment of small airways reactivity in human subjects. / Wagner, Elizabeth Marie; Bleecker, Eugene R.; Permutt, Solbert; Liu, Mark Chang Hwa.
In: American Journal of Respiratory and Critical Care Medicine, Vol. 157, No. 2, 1998, p. 447-452.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Direct assessment of small airways reactivity in human subjects
AU - Wagner, Elizabeth Marie
AU - Bleecker, Eugene R.
AU - Permutt, Solbert
AU - Liu, Mark Chang Hwa
PY - 1998
Y1 - 1998
N2 - Our knowledge of airways reactivity to inflammatory agonists is derived predominantly from tests dominated by large airway responsiveness. To determine directly, the histamine responsiveness of the smallest airways, eight normal and 11 asymptomatic asthmatic subjects were studied utilizing a wedged bronchoscope technique. A fiberoptic bronchoscope was wedged in the anterior segment of the right upper lobe and a double-lumen catheter was advanced through the working channel to its tip. With a constant flow of gas (5% CO2 in air) through one lumen of the catheter, pressure at the tip of the bronchoscope was measured with the subject breath-holding at FRC. Peripheral airways resistance (Rp) was measured at baseline and after saline, histamine (10, 50, 100 mg/ml) and isoproterenol (2 mg/ml) challenge through the bronchoscope. Baseline Rp of asthmatics (0.041 ± 0.015 cm H2O/ml/min; mean ± SE) was significantly greater than normal subjects (0.011 ± 0.003 cm H2O/ml/min; p = 0.019). The log of the concentration of histamine that caused a 100% increase in peripheral airways response was greater in the normal subjects than in the asthmatic subjects (p = 0.0114) and correlated with whole lung responsiveness to histamine in asthmatics (r = 0.847, p <0.05). Isoproterenol reversed completely the increase in Rp in normal subjects but not asthmatic subjects. The results of this study demonstrate that the resistance of the smallest peripheral airways, when measured directly, increased when challenged locally with histamine in both normal subjects and asthmatic subjects. However, the peripheral airways responsiveness was significantly enhanced in asthmatic subjects relative to normal controls.
AB - Our knowledge of airways reactivity to inflammatory agonists is derived predominantly from tests dominated by large airway responsiveness. To determine directly, the histamine responsiveness of the smallest airways, eight normal and 11 asymptomatic asthmatic subjects were studied utilizing a wedged bronchoscope technique. A fiberoptic bronchoscope was wedged in the anterior segment of the right upper lobe and a double-lumen catheter was advanced through the working channel to its tip. With a constant flow of gas (5% CO2 in air) through one lumen of the catheter, pressure at the tip of the bronchoscope was measured with the subject breath-holding at FRC. Peripheral airways resistance (Rp) was measured at baseline and after saline, histamine (10, 50, 100 mg/ml) and isoproterenol (2 mg/ml) challenge through the bronchoscope. Baseline Rp of asthmatics (0.041 ± 0.015 cm H2O/ml/min; mean ± SE) was significantly greater than normal subjects (0.011 ± 0.003 cm H2O/ml/min; p = 0.019). The log of the concentration of histamine that caused a 100% increase in peripheral airways response was greater in the normal subjects than in the asthmatic subjects (p = 0.0114) and correlated with whole lung responsiveness to histamine in asthmatics (r = 0.847, p <0.05). Isoproterenol reversed completely the increase in Rp in normal subjects but not asthmatic subjects. The results of this study demonstrate that the resistance of the smallest peripheral airways, when measured directly, increased when challenged locally with histamine in both normal subjects and asthmatic subjects. However, the peripheral airways responsiveness was significantly enhanced in asthmatic subjects relative to normal controls.
UR - http://www.scopus.com/inward/record.url?scp=0031911395&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0031911395&partnerID=8YFLogxK
M3 - Article
VL - 157
SP - 447
EP - 452
JO - American Journal of Respiratory and Critical Care Medicine
JF - American Journal of Respiratory and Critical Care Medicine
SN - 1073-449X
IS - 2
ER -